Main cast

• David Jason as DI Jack Frost
• Bruce Alexander as Superintendent Norman Mullett
• John Lyons as DS George Toolan
• Arthur White as PC Ernie Trigg

Supporting cast

Main characters

• DI William Edward "Jack" Frost (David Jason, 1992–2010) is a cynical and mercurial detective, whose talents are offset by human failings which include drinking other people's beverages, a scruffy fashion sense, and leaving his home, office, and car in states of disarray. This is marginally different from how he is portrayed in the novels, where he often lacks sympathy and has a stern, intimidating, almost vitriolic tone. He is frequently shown to avoid paperwork, leaving his subordinates to finish it. He never uses a police notebook to record evidence and other information, instead scribbling notes on various bits of paper which he stuffs in his coat pockets. Frost is widowed in the first episode. He had planned to abandon his wife, but, just as he was going to tell her, he was advised that she had been diagnosed with terminal cancer. After hearing this news, he drank heavily and deliberately angered an armed man, who shot him. As a result of subduing the man in what was perceived as a courageous, heroic act, Frost was awarded the highest British civilian award for gallantry, the George Cross, but which he describes in Episode 1 as anything but heroic. Whenever he is reminded of his award, he tends to suffer embarrassment and guilt. He is respected and admired by his colleagues and is shown to be a well-meaning but flawed man as acknowledged by troubled youth, the elderly and even by some criminals he has previously arrested. On several occasions, as in the novels, Frost breaks the law and plants evidence to get an arrest or conducts searches without permission (often gaining entry with one of his large bunch of keys, which, of course, is impossible, as he would need hundreds, and selecting the right one first time, equally unlikely) although he always has the correct suspect, as well as helping sympathetic villains or misdemeanours, often to get out of the paperwork. This type of behaviour regularly saw Frost suspended, disciplined or threatened with the same throughout the series. In the first novel, his name is shown to be Jack Frost, when DC Barnard finds his George Cross in a drawer and the inscription reads "To Jack Edward Frost". It was felt by the producers that the name Jack Frost was implausible for the TV series, so Frost was given William as his real first name, or "Billy" as his wife called him, with Jack becoming a nickname. Also in the novels, he was a chain-smoker; this again was altered in the series to have Frost quit smoking in the first episode and occasionally struggle with stopping the habit over the subsequent two series, with a penchant for unhealthy foods taking its place.
• Superintendent Stanley Mullett (Bruce Alexander, 1992–2010), a social climber concerned with appearances and ambitious for promotion, is Frost's boss and his constant foil on the job. Mullett has a love-hate relationship with Frost, whose detective skills he admires but whose people and political skills he abhors. The long-suffering Mullett frequently threatens to sack Frost, but Frost's ability to close cases usually saves him. In addition, receiving the George Cross made Frost "the Chief Constable's blue-eyed boy", thus protecting Frost from being sacked or retired by Mullett. His background in the novels was extensive; highly educated and a qualified solicitor, Mullett always drove a prestige car and was married in the series to Elspeth, who was occasionally seen, and was assured promotion to Chief Superintendent once the new police station was completed. Eventually, this promotion is turned down in a later episode thanks to yet another crisis caused by Frost who, surprisingly, gets off lightly. Frost's nickname for Mullett is "Horn-rimmed Harry" due to the traditional design of his spectacles. Frost also has a plastic, mounted grey mullet hanging on his office wall; a grey mullet is a fish commonly found in British coastal waters but not usually eaten as it is considered bland. Frost constantly tries to avoid Mullett but, just as he thinks he has managed to avoid him, Mullett spots him and generally calls out, "Ah, Jack" to which Frost replies, "Ah, there you are, sir". His first name was given in the novel "Hard Frost" as Stanley, but this novel was not written until a couple of years after the name Norman was given to the character by the writers of the TV series. In the final episode, Mr. Mullett appears to be wearing a blazer with the badge of the Army Intelligence Corps. However, in episode SE3E1, Mullett is shown wearing a blazer with an unidentified British military 'bullion' badge (but not that of the Army Intelligence Corps).

Supervising Officers

• DCI Jim Allen (Neil Phillips, 1992–1994), the first DCI to feature in the series. He and Frost get on well, sharing jokes about Mullett and concern for each other's emotions on harrowing cases. They only argue when Frost is taken off a serial rape case. He is mentioned in the second episode of the third series as "being away", but is never seen again.
• DCI Charlie Hawkes (Matthew Marsh, 1995), temporarily replaced DCI Allen. Popular with his subordinates, Hawkes' tenure is marked by his mishandling of the death of a young girl. Hawkes viciously obtains a confession from a local male with Down's Syndrome, but Frost finds the actual killer. Hawkes also inadvertently allows an imposter to pose as a visiting CID officer too.
• DCI Jim Peters (Nigel Harrison, 1996–1997), replaces temporary DCI Charlie Hawkes. He is more laid-back and humorous than Allen and appears to have a good relationship with Frost. He is the last DCI featured in the series, with Frost taking over the position in all but name for the rest of the show.
• DSI Bailey (Gwyneth Strong, 1997), is a Discipline & Complaints officer who suspends Frost, believing he's part of an evidence tampering conspiracy led by former superior Charlie Fairclough. Frost, innocent of the charge, persuades Fairclough to confess. Despite her clashes with Frost and Mullett during the case, Frost admits she is a good and effective officer.
• Chief Superintendent Babcock (Michael Cochrane, 2002), is a senior officer within Her Majesty's Inspectorate of Constabulary, reviewing Denton CID. Babcock strongly dislikes Frost, aiming to ensure his dismissal. After Frost stops a serial killer and numerous other crimes, Babcock is unable to get his wish.

Detective Sergeants

• DS George Toolan (John Lyons, 1992–2010), Jack's long-time friend and colleague with whom he shares an office. George is about the same age as Jack but a rank lower. Though he is more cautious, George is steadfastly loyal to Frost. Originally DCI Allen's assistant, he is later partnered with Frost on many occasions. In the first novel his name was George Martin, but as 'Toolan' he was retained for the series. He is known to have a wife, Mary, who confronts Frost after George is injured by falling from a flight of stairs. He was one of only three characters who stayed with the show until its demise and was the only permanent cast member to be killed off in the show's history. His death plays a role in Frost's decision to retire, as he no longer sees the office as a safe haven to escape his outside troubles without George there.
• Hazel Wallace (Caroline Harker, 1992–2003) is a young, happy-go-lucky uniformed officer. In the first novel, she was originally named Hazel Page and did not appear in any subsequent books, replaced in succession by other female officers, but was retained in the series for continuity. In the first episode she starts a relationship with DC Clive Barnard, but this quickly fizzles out when he is transferred away from Denton. Upon his temporary return, Barnard attempts to rekindle their romance, but she is in another relationship. At the end of the same series, she moves to CID. Though she ceased to be a regular, she continued to make guest appearances in later series and was promoted to detective sergeant. She also gave birth to a daughter whom she brought into the station on one occasion. In the second series she almost fell victim to a serial rapist but overpowered him in her apartment.
• Clive Barnard (Matt Bardock, 1992; 1995-1997) was the nephew of the Chief Constable and newly promoted into CID when he first meets Frost. Most people believe he has only got into CID through his family connections, but Frost sees beyond that and takes Barnard under his wing. Whilst Barnard is transferred away from Frost after only a brief tenure, the two still work together occasionally on cases over the following years. Later promoted to DS, Barnard is shot dead in the line of duty, saving Frost's life. Frost, saying Clive is the real hero, places his George Cross on Clive's body to be buried with him. He appeared in the first novel and was carried across onto the series for continuity.
• Sandy Gilmore (Tony Haygarth, 1992) is a chain-smoking copper of the 80s, who is seconded to Denton CID to cover the number of officers on sick leave. Although he inappropriately tries to smoke in the houses of people he is interviewing and gets a reprimand, Frost begins to like his instinctive, proactive sense of policing.
• Maureen Lawson (Sally Dexter, 1994; 2003) is a strong-willed, hardworking gay detective who sometimes lets her personal judgement get in the way. She left divisional CID after a burglary victim was stabbed by her jealous lover, though she was saved from further repercussions by Frost's protection. She later returned to help Frost investigate the murder of a local businessman.
• Frank Nash (Neil Stuke, 1996) is a young, hardworking officer who, after a move to Denton from London, is trying to settle down with his wife and start a family. However, the long hours that Frost makes him work begin to strain his marriage, so he and his wife decide to up sticks and move back to London. Frost tipped Frank for good success and wished him all the best.
• Rab Prentice (Russell Hunter, 1996) is an old-fashioned, laidback Scottish detective due for retirement. His constant bemoaning of sex and relationships, and repeated remarks to Frost about old age, easily rile the inspector. To Frost's shock, Prentice applies for the "ill health pension" at the end of the episode (citing "stress") in order to retire early and embark on a relaxed lifestyle.
• Liz Maud (Susannah Doyle, 1997) is an ambitious, high-flying detective who transferred to Denton from the West End. Whilst investigating child abuse, Maud inadvertently risks Frost's career when a report she files implies Frost went easy on a murder suspect. After finding the real killers, Maud returns to London when Mullett refuses her application to become an Acting DI.
• Billy "Razor" Sharpe (Philip Jackson, 1999; 2005) is nicknamed "Razor" because he's not very sharp. However, Frost rates him because he's a "plodder" who is methodical in his work. After once working with Frost, Sharpe returns to support him during an investigation into a serial killer, having previously worked on a similar case. Here, Sharpe is stabbed but non-fatally by the killer.
• Bill Dorridge (Paul Jesson, 1999–2000) was assigned by newly promoted Assistant Commissioner Cremond to temporarily replace DS George Toolan, who was temporarily reassigned to "community duties" due to disciplinary action. Dorridge is an amiable, by-the-book detective with experience in most investigative sections, especially liking commercial fraud.
• Terry Reid (Robert Glenister, 2001–2003) is a tough London detective who has suffered from alcohol and drug addictions. He has often been in trouble for his extreme methods, though he has mellowed by the time he works with Frost. Working together on several cases, Frost and Reid become friends. Frost also learns about an act of bravery by Reid, for which he was awarded the Military Medal.
• Annie Marsh (Cherie Lunghi, 2008) is a hardworking detective from Manchester who is not keen on Frost's methods of cutting corners and bending the rules to get a result. Once, before she and Frost were posted at Denton, she reported him for endangering the life of a young PC and being unprofessional – something he took to heart and still remembers to this day.

Detective Constables

• Vic Webster (George Anton, 1992) is briefly Frost's partner. When PC Shelby, a confident uniformed officer with a reputation as a ladies' man, is murdered, Frost investigates and finds Webster killed him because Shelby had been having an affair with his wife. Webster denies the charges, but Frost is ultimately successful in finding evidence to prove his case, resulting in Webster being sentenced for his crime.
• Carl Tanner (Lennie James, 1994) is a black officer seconded to support Frost with investigations into a murder and burglaries within a black majority area of Denton. Appointed by Mullett purely for public relations, Tanner nonetheless proves himself as an able, dedicated officer. However, despite their newly formed working relationship, Tanner is reassigned again by Mullett following the conclusion of the cases.
• Martin Costello (Neil Dudgeon, 1994) is an unpopular officer with a negative perception of him when he becomes Frost's partner. This is due to Costello being reassigned to Denton CID after punching a DCI in his former unit. Moody, sullen and cynical, it's only when Frost issues a stern warning about Costello's conduct that he lightens up and shows Frost exactly why he's a good officer.
• Giles (Sarah Kirkman, 2003) is an officer protecting trial witness Cathy Thompson, as Cathy awaits to testify against gangland villain Jack Flynn. When one of Flynn's hitmen attempts to murder Cathy, Giles scares the hitman off. However, because her colleague DC Chandler had taken an unauthorised trip to the shop at the same time, Giles and Chandler are suspended and told bluntly their careers are over.
• Chandler (Robert Horwell, 2003) is an officer protecting trial witness Cathy Thompson. Chandler's negligence results in Flynn's hitman nearly murdering Cathy, prompting Cathy to flee with her son Robbie. Alongside his partner Giles, Chandler is suspended and bluntly told his police career is as good as obliterated.

Uniformed officers

• PC Ernie Trigg (Arthur White, 1994–2010), the police archivist. He helps Frost with knowledge of known associates and crime methods he has collected over the years that are not available in the police computer system. He and Frost knew each other long before they were stationed at Denton.
• Sgt Alan Hadley (Sean Blowers, 2003), is a senior firearms officer overseeing a manhunt for gangland hitman Gary Tinley. Whilst chasing Tinley, Hadley's partner PC Kenny Russell is killed, supposedly by Tinley. However, Frost and Reid discover Hadley actually murdered Russell and framed Tinley as revenge for Russell having an affair with his wife Sheila. Before being arrested, Hadley commits suicide out of guilt.
• WPC Claire Toms (Colette Brown, 1996), serves as Frost's partner when recovering a kidnap victim held to ransom. With training in kidnap recovery and hostage negotiation, Toms proves to be a useful and capable partner despite her youth and junior rank. After the successful conclusion of the operation, Toms returns to other duties.
• PC Craven (Ian Mercer, 1996), a patrol officer Frost encounters a few times during investigations. When Frost is rendered homeless after a house fire and moves into the shared accommodation block for police officers, Craven is one of his flatmates. Craven is perturbed to find food from the shared kitchen going missing, unaware that Frost himself is the culprit.
• WPC Lindsey Hunter (Katrina Levon, 1996), is temporarily seconded into CID to support Frost's investigation of an assault on a student at Denton University. After the case is solved and the culprit apprehended, Hunter returns to uniform, earning Frost's respect and gratitude for her competent conduct during the investigation.
• WPC Holland (Miranda Pleasence, 1997-1999), attracts Frost's ire during an investigation into an elderly woman murdering her husband. Frost, sympathetic to the elderly woman's plight given the long-term abuse she suffered from her husband, chastises Holland's callous attitude. Holland is also romantically involved with DS Barnard and is devastated by his death in the line of duty.
• WPC Ronnie Lonnegan (Michelle Joseph, 2002), is temporarily assigned to CID to support Frost when Denton station is under inspection. A black female officer who is recently widowed, Lonnegan dismisses a series of early gaffes from Frost, and the two work well together whilst hunting a serial killer stalking Denton. After the killer is caught, Lonnegan returns to her former duties.
• WPC Tracy Miller (Daniele Lydon, 2003), is assigned to protect Cathy Thompson and her son Robbie, as Cathy is a key witness in a major murder trial against gangland criminal Jack Flynn. Miller is shot and badly wounded by Flynn's hitman, resulting in her losing an arm. The brutal crime drives Frost on to catch Flynn and those responsible, as Miller was a recruit of his.
• PC Kenny Russell (Stuart Bowman, 2003), is an armed response officer, working on the manhunt for Gary Tinley, a gangland hitman. Russell is shot and killed, supposedly by Tinley. However, Frost and Reid discover Russell's partner, Alan Hadley, killed Russell as he'd been having an affair with his wife, Sheila.

Other Service Personnel

• Sandy Longford (Bill Stewart, 1992-1999), Denton Evening News journalist who has a longstanding love–hate relationship with Frost, since each party is often either useful or a nuisance to the other. Longford regularly pesters Frost for confidential details of ongoing cases to report on, although Frost often uses Longford's local knowledge and contacts to help solves cases.
• Captain Carlisle (Ralph Brown, 1996), a member of the Royal Military Police and Special Investigation Branch forced to partner with Frost during an investigation into the murder of a Territorial Army volunteer. Whilst Frost and Carlisle initially clash, they eventually work together to solve the murder and uncover other crimes, including the illegal selling of weapons and blackmail.
• Eileen Cleary (Helen Masters, 2003), is a solicitor with the CPS assigned to the trial of gangland villain Jack Flynn. Cleary strikes up a rapport with key witness Cathy Thompson, but Terry Reid views Cleary negatively after previous experiences. After repeated attempts by Flynn's men to murder Cathy, Frost deduces Cleary as Flynn's informant. Upon being arrested, Cleary reveals Flynn is the father of her son, which informs her betrayal.
• Martine Phillips (Sara Stewart, 2005), is a criminal profiler assigned to help Denton CID investigate the brutal murder of a mother. Phillips establishes they're dealing with a serial killer seeking sexual gratification and is threatened by the killer during the case. DS Sharpe develops a crush on her, but Phillips rejects any kind of romantic or sexual attention from him before leaving.
• Christine Moorhead (Phyllis Logan, 2010), an RSPCA officer who works with Jack to help crack his final case, involving dog fighting. She later becomes a key witness in a murder, and the couple becomes closer. Jack finds himself bonding with her teenage children and, as such, the pair decide to marry. However, on their wedding day, her ex-husband, in a drunken fit of jealousy, tries to kill Jack by ploughing into the side of his car in his 4x4. However, he misses, instead killing DS George Toolan. It is on the strength of his relationship with Christine that Jack decides to retire, now that he has something outside the station to live for.

Romantic Interests

• Shirley Fisher (Lindy Whiteford, 1992–2000), the nurse who cared for Jack's terminally ill wife. She later develops a relationship with Jack, which continues for some time. The relationship is strained when Shirley realises she can't cope with the demands of Jack's job and how he frequently stands her up on important occasions. The pair separate, although Jack on several occasions seems to regret their parting.
• Rosalie Martin (Isla Blair, 1996-1997), is a widow who encounters Frost when he investigates the murder of a gigolo whom Rosalie had been seeing. A spark develops, and Rosalie promises to contact him when she's ready to move on romantically. She does so a year later, leading her and Frost to begin a relationship. However, this is brief and ends when Rosalie confesses she has feelings for another man.
• Kitty Rayford (Gwyneth Powell, 1997), an ex-prostitute who Jack knew in her youth. She and Jack meet again in "Penny for the Guy" when he crashes into her car after skipping a temporary red light. The pair maintain a physical relationship until they go their separate ways in "True Confessions" as Frost realises he cannot give Kitty the ongoing companionship she desperately desires.
• Dr. Pam Hartley (Susan Penhaligon, 2002), is a criminal profiler who Jack meets at a training course. Frost seeks Pam's advice about a suspected serial killer and the two also begin a relationship. However, the killer kidnaps Pam because she had previously recommended he be taken into care as a child. Frost saves Pam from being murdered, but sometime later, off-screen, they break up.