Buffalo Bills

Lamonica was drafted by the Buffalo Bills in the 24th round of the 1963 AFL draft. He was also selected by the two-time defending NFL champion Green Bay Packers in the 12th round of the 1963 NFL draft. He chose to go with the Bills, as he perceived his chances of playing were better there. In his rookie year, he played sparingly in games with Jack Kemp being the primary quarterback while Lamonica came into duty after injuries or ineffectiveness, which led to him being dubbed "the Fireman". However, he was tasked to start the last two games for the Bills. In each, he led them to victory, notably going 10-for-16 with 115 yards with a touchdown in a 45–14 win over the New York Jets. For the season, he had 33 completions on 71 attempts for 437 yards, with three touchdowns and four interceptions.^[4] In the tiebreaker playoff for the division title, he came on for Kemp late in the game, going 9-for-24 for 168 yards with a touchdown and three interceptions, as the Bills lost 26–8 at home to the Boston Patriots.^[5]

Lamonica had much of the same in terms of playing time in 1964, going 55 of 128 with 1,137 yards with six touchdowns and eight interceptions. On rushing, he was most efficient, having 55 carries for 289 yards (a 5.3 average per carry) for six touchdowns, which was tied for the most in the league alongside others such as Sid Blanks and his teammate Cookie Gilchrist. He started one of the last games of the season against the Denver Broncos, going 6-of-21 for 89 yards with a touchdown and interception, but Buffalo prevailed 30–19.^[6] In 1965, the same was true once again. He went 29 of 70 for 376 yards, with three touchdowns and six interceptions. For the third and final season, he started a game for the Bills, going 3-of-14 for 83 yards with a touchdown and interception in a 29–18 win over the Houston Oilers.^[7] For his fourth and final year in Buffalo in 1966, he went 33-of-84 for 549 yards, having four touchdowns and five interceptions. In the three Buffalo runs to the AFL title game from 1964 to 1966, he had minimal participation, throwing only one pass.^[8]

Oakland Raiders

On March 14, 1967, Lamonica was traded to the Oakland Raiders with Glenn Bass for Art Powell and Tom Flores. He played with Oakland until his final year in 1974. With John Rauch at the helm as coach, Lamonica thrived from the start. In 1967 he threw 220-for-425 for 3,228 yards with thirty touchdowns and twenty interceptions while rushing for four touchdowns. The team went 13–1 in the regular season and won the division title with Lamonica at the helm; in the AFL title game against the Oilers on December 31, he went 10-of-24 for 111 yards with two touchdowns as the Raiders won, 40–7, to win their first championship as a franchise. Two weeks later, he faced off against the Green Bay Packers in Super Bowl II. He went 15-of-34 for 208 yards, with two touchdowns and one interception (returned by Herb Adderley for a touchdown), as the Raiders lost 33–14. Lamonica was given the American Football League Most Valuable Player Award for the season by United Press International, the Associated Press, and The Sporting News.^[9]

In 1968 he was efficient once again, going 206-of-416 for 3,245 yards in thirteen games (Lamonica missed the ninth game of the season, which George Blanda started). He threw 25 touchdowns and fifteen interceptions. His longest completed pass was 82 yards, his longest as a Raider for his career. He threw 249.6 yards per game, a career high. In the infamous Heidi Game, he went 21-of-34 for 311 yards with four touchdowns and two interceptions, with his final touchdown to Charlie Smith being the deciding points in a nail-biting victory.^[10] The Raiders charged to a 12–2 record, tied with Kansas City for the best record in the Western Division. They trounced the Chiefs 41–6 to return to the AFL championship. Playing against the New York Jets at Shea Stadium, Lamonica went 20-of-47 for 401 yards with a touchdown, but the Jets rallied to defeat Oakland 27–23.^[11]

Lamonica was consistent once again in 1969 (the last for the AFL and first for John Madden as coach). He had career highs with 221 completions, 426 attempts, 3,302 yards, 34 touchdowns, and 25 interceptions. He had 235.9 yards per game. The Raiders went 12–1–1, winning the Western Division once again. On October 19, against the Buffalo Bills, Lamonica set a new record with six touchdown passes in the first half, a record that has been matched only once, by Aaron Rodgers against the Chicago Bears on November 9, 2014. Lamonica's team went to the playoffs once again, which had been expanded to four teams for the final year of the AFL. In the divisional playoff game versus overmatched Houston, he threw 13-of-17 for 276 yards with six touchdowns and one interception for a 56–7 victory. In the AFL Championship Game (the last game between two AFL teams), facing the Chiefs in Oakland, Lamonica threw 15-of-39 for 167 yards and three interceptions as the Chiefs won, 17–7, to advance to Super Bowl IV. Lamonica was given the American Football League Most Valuable Player Award for the season by United Press International and The Sporting News, with Joe Namath being named Most Valuable Player by the Associated Press.^[12][13] It was in Oakland that Lamonica's affinity for - and talent in - long passes earned him the nickname "the Mad Bomber".

Lamonica regressed a bit for 1970, throwing 179-of-356 for 2,516 yards with 22 touchdowns and fifteen interceptions as the team went 8–4–2. The team was aided by the fourth quarter heroics of George Blanda, who came off the bench for Lamonica in five straight games (games six to ten) in the fourth quarter, helping them win four games and tie once. The team snuck through into the NFL playoffs, edging out Kansas City for the newly-installed AFC West division title. In their divisional playoff, Lamonica went 8-of-16 for 187 yards and two touchdowns as the Raiders prevailed, 21–14, over the Miami Dolphins in Oakland. In the AFC Championship Game against the Baltimore Colts, Lamonica went 1-of-4 for six yards before a hit by Bubba Smith resulted in him being taken out for Blanda as the Raiders were beaten, 27–17.^[14]

On September 17, 1972, Lamonica had a perfect passing rating of 158.3. In a game that was started by Ken Stabler with additional play from George Blanda, Lamonica stepped in to throw 8-of-10 for 172 yards with two touchdowns, turning a 20–7 trouncing by the Pittsburgh Steelers into a 34–28 loss.^[15] Lamonica started the remaining thirteen games for the season. He had 149 completions on 281 attempts for 1,998 yards, having a career high 53.0 completion percentage while throwing eighteen touchdowns and twelve interceptions. The team went 10-2-1 for the year and won the Western Division title. In the divisional playoff game that year against Pittsburgh at Three Rivers Stadium on December 23, he went 6-of-18 for 45 yards with two interceptions. Ken Stabler stepped in late in the game, and while he only went 6-of-12 for 57 yards, his thirty yard rush for a touchdown gave the Raiders a late 7–6 lead with less than two minutes remaining. However, Franco Harris caught a tipped pass from Terry Bradshaw in what is now known as the Immaculate Reception to give Pittsburgh a 13–7 victory. It was Lamonica's last playoff appearance.^[16]

With Lamonica, the Raiders won four straight Western Division titles (three AFL and one AFC) and one American Football League championship. Lamonica was a three-time American Football League All-Star and twice was selected as the AFL's Most Valuable Player, in 1967 and 1969. Lamonica went 66–16–4 (.791) as a starter, second best in NFL history (Otto Graham is the highest at .810). In the American Football League, Lamonica's winning percentage as a starter was .900, on 40 wins, 4 losses and 1 tie in 45 games, the best ever in the AFL. Although excellent at man-for-man coverage, he had a hard time reading zone defenses, more prevalent in the 1970s, and his throwing was sometimes inaccurate. As a Raider starter from 1967 to 1972, his best completion average was 53.0% (in 1972).^[17]

Lamonica was replaced in 1973 by future Pro Football Hall of Famer Ken Stabler, who was better at reading defenses and more accurate, leading the 1976 team to victory in Super Bowl XI.^[18]

World Football League

Lamonica was the 25th player to jump from the NFL to the World Football League (WFL) on April 16, 1974, when he signed a multiyear contract to join the Southern California Sun in 1975.^[19] He went 9-of-19 for ninety yards and one touchdown in limited playing time in his only season in the WFL which folded in late October of that year.^[20]