On September 1, 2005, Trout made his professional boxing debut at the age of 19 at the Isleta Casino & Resort in Albuquerque, New Mexico.
Three months later, Trout was taken the six round distance when he defeated Mexican boxer Julio Perez with scores of (60–54, 60–54 and 59–55).
In November 2009, he beat Taronze Washington to win the vacant WBC Continental Americas light middleweight title.
While waiting for his opportunity to fight for Miguel Cotto for the championship title, Austin ended up working with DeAngelo Singleton to help with early stages of PR.
[7][8][9] In April 2011, soon after winning the WBA (Regular) title, Trout's first defence was announced to take place against mandatory challenger David Alonso López (42–12, 23 KOs) on June 11 in Mexico.
[10] Trout dropped López in round 11 as he went on to successfully retain his WBA "regular" title in a 12-round unanimous decision win with the judges scores of 119–109, 117–110 and 118–109 in his favour.
[15][16][17] By October, a deal was set for Trout to defend his title against another Australian boxer, former welterweight champion Frank LoPorto (15–4, 7 KOs), who was ranked #14 by the WBA on November 11 at the Cohen Stadium in El Paso, Texas.
[21] The purse bids never took place and in April, Trout announced he was close to finalizing a deal with former WBO champion Sergiy Dzinziruk (37–1, 23KOs) on August 25, his biggest fight to date.
[22] Days later, it was reported that Trout could instead fight Ring Top 10 Delvin Rodriguez (26–5–3, 14 KOs) on the June 2 at the Home Depot Center in Carson, California.
2 ranked light middleweight Miguel Cotto (37–3, 30 KOs) on December 1 at Madison Square Garden in New York City.
The fight was supposed to take place during Cinco de Mayo weekend as the co-main event of the Floyd Mayweather Jr. bout against Robert Guerrero; however, due to a contract disagreement between Álvarez and Mayweather regarding their potential fight on September 14, 2013, Álvarez opted to headline his own card.
[41][Video 1] Although the last score card (118–109) created controversy, the majority of sport analysts had Álvarez winning by at least 2 points.
[42] Immediately after the bout, Trout stated that he hadn't underestimated Álvarez but that he trained to fight a completely different fighter.
[43][44] After losing to Álvarez, Trout next fought Cuban boxer Erislandy Lara (18–1–2, 12 KOs) for his WBA Interim light middleweight title.
[45] Lara, however, put on a dominant performance as he immediately nullified Trout's offense using deft footwork and clean punching.
In outclassing Trout, Lara scored a knockdown in round eleven via straight left hand.
His first comeback fight took place in August 2014 against former WBO light middleweight title challenger Daniel Dawson (40–3–1, 26 KOs) in a 10-round bout.
Trout was knocked down twice in round 3 via straight right hands, but rallied on and won a unanimous decision in what was supposed to be an easy tune-up.
[52][53] On May 9, 2015, Trout fought 33 year old Luis Galarza (20–3, 14 KOs) at the State Farm Arena in Hidalgo, Texas.
The card also included top light middleweights Erislandy Lara, Vanes Martirosyan and Jermell Charlo.
[63] On May 31, 2017 The Ring TV announced a deal was in place for Trout to challenge undefeated American boxer Jarrett Hurd (20–0, 14 KOs) for his newly won IBF light middleweight title on July 29 on the undercard of Mikey Garcia vs. Adrien Broner in New York.
[64] On July 20, Boxing Scene reported the fight was being lined up to take place on September 30, 2017, as part of a light middleweight double header alongside Jermell Charlo's WBC title defence against Erickson Lubin.
Because Hurd was granted an exception from the IBF to make a voluntary defence, however the winner must fight mandatory challenger Cedric Vitu (46–2, 19 KOs) by December 29, 2017.
[65] On August 24, Ringtv announced the fight would take place as part of a light middleweight triple-header at the Barclays Center in New York City on October 14, 2017.
In the middle rounds, Hurd was able to stifle Trout's movement, making the fight more of a brawl, with both fighters trading power shots.
[67] For the fight, Hurd earned $330,000, while Trout, who was stopped inside the distance for the first time since turning professional, was paid $225,000.
[68][69] On January 11, 2018, it was announced that Trout would make a ring return against Colombian boxer Juan De Angel on the Devon Alexander vs. Victor Ortiz undercard on February 17 at the Don Haskins Center on the UTEP campus in El Paso, Texas.
[72] At a Showtime press conference on January 24, 2018, it was announced that Jermell Charlo (30–0, 15 KOs) would make a third defence of his WBC title on June 9 on the undercard of Santa Cruz vs.
[80] On April 11, 2019, it was reported that Trout would fight 31-year-old former world title challenger Terrell Gausha (21–1, 10 KOs) in a 10-round light middleweight bout, headlining at the Beau Rivage Resort Casino in Biloxi, Mississippi, on May 25, on Fox Sports 1.
[87] Trout is scheduled to make his second title defense against undefeated contender Carlos Trinidad-Snake on April 4, 2025 at BKFC Dubai: Day 1.