2000–2004

Peralta turned pro in 2000, and had his best year in his singles career in 2003, year which he won a challenger tournament, the BH Tennis Open International Cup in Belo Horizonte. He retired in 2005.

2007–2008

He made a comeback in 2007 at ITF Futures tournaments. Julio competed throughout 2008, but he suffered an injury the next year.

2011: Second comeback

He made his comeback (after long, exhausting, two-year injury) in the 2011 Sparkassen Open, winning comfortably the first two qualifying rounds, against Stefan Seifert and David Goffin (no. 220). In the main tournament, he defeated Victor Crivoi.

2014: Third comeback

After a long hiatus, he returned in September at the 2014 Napa Valley Challenger doubles tournament partnering Matt Seeberger as a wildcard pair.

In early November, he won the titles in both singles and doubles USA F30 tournament, not dropping a single set in the main draw in both tournaments. In Chile F9 tournament he made the singles final, losing to Hans Podlipnik Castillo and the following week won the doubles tournament in Chile F10 partnering Seeberger.

2015: New partnership and Challenger Tour success

Peralta played many Challenger Tour tournaments during the year, reaching seven finals and winning four, partnering Horacio Zeballos in three of these titles. With the victories, Peralta rose almost 400 positions in the rankings, ending the year at No. 105.

2016: Three ATP Doubles titles

He broke through onto the ATP World Tour doubles circuit in 2016, winning the Brazil Open, the Swiss Open and the Moselle Open with Horacio Zeballos. He won his first match in a Grand Slam at the French Open, partnering Denis Kudla, but the duo lost in the second round. Peralta also won six challenger tournaments, partnering Zeballos in four, in one with Dennis Novikov, and at Santiago with countryman Hans Podlipnik. Peralta tied with Matt Reid and John-Patrick Smith for most Challenger titles in doubles for the year. Peralta finished the year ranked No. 44 in the world in doubles, and the highest ranked Chilean player in singles or doubles, record he has held since then.

2017: Another title, French Open quarterfinals, top 30 debut

Peralta and Zeballos reached the final of the Ecuador Open, but lost to James Cerretani and Philipp Oswald. They went on to win the U.S. Men's Clay Court Championships. At the French Open, he partnered Zeballos to reach the quarterfinals. This saw his ranking jump to a career high of No. 35.

In the rest of the year, Peralta reached two more tournament finals with Zeballos, and another one with Santiago González, with whom he reached quarterfinals at the 2017 Shanghai Rolex Masters too.

Peralta ended the year at World No. 29, his best position yet.

2018: First ATP 500 & one more titles

Peralta had a slow beginning of the year, with semifinals at 2018 ASB Classic as the only notable result. Julio and Horacio Zeballos reunited for attempting a defense of their title in the U.S. Men's Clay Court Championships, but they lost in first round. They also tried to imitate their past year quarterfinals run on the French Open, but they lost in second round. Partnering with Roman Jebavý, they reached semifinals of the 2018 Antalya Open.

Peralta and Zeballos partnered again for the 2018 Wimbledon and won over 16th seeds Max Mirnyi and Philipp Oswald in first round, but then lost in second round. The partnership went on and they won the 2018 Swedish Open, defeating in the final the Italian pair Simone Bolelli and Fabio Fognini. The following week Peralta and Zeballos won another title, the 2018 German Open, his first on the ATP 500 level, defeating Oliver Marach and Mate Pavić in the final.

2022: Back on the ATP tour

After almost 4 years of hiatus, Peralta came back on the ATP tour in April where he entered the 2022 BMW Open with Franko Škugor with a protected ranking^[4] and next at the Italian Open as an alternate pair also with Škugor where they won their first round match against top 50 players Tomislav Brkić and Nikola Ćaćić.^[5]

Doubles: 10 (6 titles, 4 runner-ups)

Result	W–L	Date	Tournament	Tier	Surface	Partner	Opponents	Score
Win	1–0	Feb 2016	Brasil Open, Brazil	250 Series	Clay	Horacio Zeballos	Pablo Carreño Busta David Marrero	4–6, 6–1, [10–5]
Win	2–0	Jul 2016	Swiss Open, Switzerland	250 Series	Clay	Horacio Zeballos	Mate Pavić Michael Venus	7–6(7–2), 6–2
Win	3–0	Sep 2016	Moselle Open, France	250 Series	Hard (i)	Horacio Zeballos	Mate Pavić Michael Venus	6–3, 7–6(7–4)
Loss	3–1	Feb 2017	Ecuador Open, Ecuador	250 Series	Clay	Horacio Zeballos	James Cerretani Philipp Oswald	3−6, 1−2 ret.
Win	4–1	Apr 2017	U.S. Men's Clay Court Championships, US	250 Series	Clay	Horacio Zeballos	Dustin Brown Frances Tiafoe	4–6, 7–5, [10–6]
Loss	4–2	Aug 2017	Winston-Salem Open, US	250 Series	Hard	Horacio Zeballos	Jean-Julien Rojer Horia Tecău	3−6, 4−6
Loss	4–3	Sep 2017	St. Petersburg Open, Russia	250 Series	Hard (i)	Horacio Zeballos	Roman Jebavý Matwé Middelkoop	4–6, 4–6
Loss	4–4	Oct 2017	European Open, Belgium	250 Series	Hard (i)	Santiago González	Scott Lipsky Divij Sharan	4–6, 6–2, [5–10]
Win	5–4	Jul 2018	Swedish Open, Sweden	250 Series	Clay	Horacio Zeballos	Simone Bolelli Fabio Fognini	6–3, 6–4
Win	6–4	Jul 2018	German Open, Germany	500 Series	Clay	Horacio Zeballos	Oliver Marach Mate Pavić	6–1, 4–6, [10–6]

Singles (8–6)

Outcome	No.	Date	Tournament	Surface	Opponent	Score
Runner-up	1.	28 August 2000	Peru F1, Peru	Clay	Júlio Silva	6–7(4–7), 6–3, 3–6
Runner-up	2.	4 December 2000	Chile F9, Chile	Clay	Patricio Rudi	6–3, 6–7(2–7), 0–6
Runner-up	3.	16 July 2001	Romania F3, Romania	Clay	Gabriel Moraru	6–7(6–8), 6–7(3–7)
Winner	1.	3 September 2001	Peru F2, Peru	Clay	Yohny Romero	6–3, 6–3
Winner	2.	24 September 2001	Bolivia F2, Bolivia	Clay	Phillip Harboe	6–3, 6–4
Runner-up	4.	8 October 2001	Paraguay F1, Paraguay	Clay	Sebastián Decoud	3–6, 1–6
Winner	3.	14 April 2003	Chile F3, Chile	Clay	Phillip Harboe	4–6, 6–4, 6–2
Winner	4.	28 July 2003	Belo Horizonte, Brazil	Hard	Danai Udomchoke	7–6(8–6), 1–6, 6–1
Winner	5.	2 August 2004	Chile F1-A, Chile	Clay	Damián Patriarca	6–2, 6–1
Runner-up	5.	9 August 2004	Chile F1-B, Chile	Clay	Cristian Villagrán	4–6, 4–6
Winner	6.	27 October 2008	Chile F4, Chile	Clay	Jorge Aguilar	6–4, 6–2
Winner	7.	3 November 2008	Chile F5, Chile	Clay	Bruno Tiberti	6–0, 6–2
Winner	8.	4 November 2014	USA F5, United States	Clay	Jean-Yves Aubone	6–2, 6–1
Runner-up	6.	1 December 2014	Chile F9, Chile	Clay	Hans Podlipnik Castillo	2–6, 3–6

Doubles (18–10)

Outcome	No.	Date	Tournament	Surface	Partner	Opponents	Score
Runner-up	1.	1 October 2001	Bolivia F3, Bolivia	Clay	Felipe Parada	Federico Cardinali Sergio Elias	7–5, 2–6, 3–6
Runner-up	2.	22 April 2002	Jamaica F3, Jamaica	Hard	Kepler Orellana	Diego Ayala Adam Kennedy	5–7, 6–3, 3–6
Runner-up	3.	20 January 2003	USA F2, USA	Hard	Felipe Parada	Ignacio Hirigoyen Tripp Phillips	4–6, 2–6
Runner-up	4.	27 January 2003	USA F3, USA	Hard	Felipe Parada	Ryan Sachire Tripp Phillips	w/o
Winner	1.	27 October 2008	Chile F4, Chile	Clay	Mathieu Guenat	Cristóbal Saavedra Corvalán Ángel Torres	6–2, 6–2
Winner	2.	3 November 2014	USA F30, USA	Clay	Matt Seeberger	Cătălin-Ionuț Gârd Alex Rybakov	6–3, 6–4
Winner	3.	8 December 2014	Chile F10, Chile	Clay	Mathieu Guenat	Martín Cuevas Gustavo Guerses	6–2, 6–3
Winner	4.	15 December 2014	Chile F11, Chile	Clay	Ricardo Urzúa-Rivera	Nicolás Arreche Tomás Lipovšek Puches	7–5, 6–0
Winner	5.	22 December 2014	Chile F12, Chile	Clay	Hans Podlipnik	Ariel Behar Gonzalo Lama	7–6(7–3), 6–2
Winner	6.	23 February 2015	Panama F1, Panama	Clay	Darian King	Iván Endara Eduardo Agustín Torre	w/o
Winner	7.	2 March 2015	Nicaragua F1, Nicaragua	Clay	Juan Sebastián Gómez	Keith-Patrick Crowley Hans Hach Verdugo	6–3, 6–3
Runner-up	5.	20 April 2015	Savannah, United States	Clay	Dennis Novikov	Guillermo Durán Horacio Zeballos	4–6, 3–6
Winner	8.	27 April 2015	Tallahassee, United States	Clay	Dennis Novikov	Somdev Devvarman Sanam Singh	6–2, 6–4
Winner	9.	1 June 2015	USA F16-A, USA	Hard	Matt Seeberger	Tennys Sandgren Rhyne Williams	3–6, 6–3, [10–8]
Runner-up	6.	8 June 2015	Moscow, Russia	Clay	Matt Seeberger	Renzo Olivo Horacio Zeballos	5–7, 3–6
Runner-up	7.	13 July 2015	Poznań, Poland	Clay	Matt Seeberger	Mikhail Elgin Mateusz Kowalczyk	6–3, 3–6, [6–10]
Winner	10.	12 October 2015	Corrientes, Argentina	Clay	Horacio Zeballos	Guillermo Durán Máximo González	6–2, 6–3
Winner	11.	2 November 2015	Bogotá, Colombia	Clay	Horacio Zeballos	Nicolás Barrientos Eduardo Struvay	6–3, 6–4
Winner	12.	9 November 2015	Buenos Aires, Argentina	Clay	Horacio Zeballos	Lucas Arnold Ker Guido Andreozzi	6–2, 7–5
Runner-up	8.	4 January 2016	Mendoza, Argentina	Clay	Horacio Zeballos	Máximo González José Hernández-Fernández	6–4, 3–6, [1–10]
Winner	13.	25 January 2016	Bucaramanga, Colombia	Clay	Horacio Zeballos	Sergio Galdós Luis David Martínez	6–2, 6–2
Winner	14.	7 March 2016	Santiago, Chile	Clay	Hans Podlipnik	Facundo Bagnis Máximo González	7–6(7–4), 4–6, [10–5]
Winner	15.	25 April 2016	Tallahassee, United States	Clay	Dennis Novikov	Peter Luczak Marc Polmans	3–6, 6–4, [12–10]
Runner-up	9.	30 May 2016	Prostějov, Czech Republic	Clay	Hans Podlipnik	Aliaksandr Bury Igor Zelenay	4–6, 4–6
Runner-up	10.	25 July 2016	Prague, Czech Republic	Clay	Facundo Argüello	Julian Knowle Igor Zelenay	4–6, 5–7
Winner	16.	25 July 2016	Genova, Italy	Clay	Horacio Zeballos	Aliaksandr Bury Andrei Vasilevski	6–4, 6–3
Winner	17.	10 October 2016	Buenos Aires, Argentina	Clay	Horacio Zeballos	Sergio Galdós Fernando Romboli	7–6(7–5), 7–6(7–1)
Winner	18.	17 October 2016	Santiago, Chile	Clay	Horacio Zeballos	Máximo González Sergio Galdós	6–3, 6–4