As a teenager, Chávez Jr. endured some difficult moments, including a widely publicized relationship between his father and actress Salma Hayek and the subsequent divorce of his parents.

[9] On 26 September 2003, at Super Featherweight (130 lbs), he won his professional debut by outpointing Jonathan Hernandez over six rounds in Chávez Jr.'s native Culiacán, Sinaloa.

However, during training for the bout, Alfonso tore some ligaments in his left elbow and had to withdraw from the card and undergo a few months of rehab.

For his part, Chávez Jr. was set to fight Paweł Wolak as a replacement bout, but after adjusting the weight limit for said match to 165 lbs, Chávez Jr. had to pull out due to the flu messing up his training and weight loss and then in January he went on to beat title contender Billy Lyell.

[15] On 4 June 2011, Chávez defeated WBC Middleweight Champion Sebastian Zbik to win his first world title at the Staples Center in Los Angeles, California, taking a major step toward establishing his own legacy while his famous father looked on.

[16] The fight drew 1.5 million viewers on HBO: Boxing After Dark making it the most viewed since 2007 when Paulie Malignaggi fought Lovemore Ndou.

In the fifth round, Chávez hurt Manfredo with a hard right hand and unloaded a flurry when the challenger wobbled and backed up on the ropes.

He didn't answer with any punches and referee Laurence Cole finally stepped in to call it at 1 minutes, 52 seconds.

Chávez Jr. recovered from a slow start he blamed on leg cramps and stopped Andy Lee at 2:21 of the seventh round to retain the WBC Middleweight title.

[17] With the victory, Chávez put himself in position for a title-unification fight with recognized World Middleweight Champion Sergio Martinez.

[26] A deal was reached for Chávez and Sergio Martínez (49-2-2, 28 KO) to fight on 15 September 2012, at the Thomas & Mack Center in Las Vegas for the Unified WBC and The Ring Middleweight Championship.

Chávez won via unanimous decision claiming the vacant WBC Continental Americas super middleweight title.

[35][36] Chávez announced that he would be returning on 18 July 2015 against fellow Mexican Marcos Reyes (33-2, 24 KOs) at the Don Haskins Convention Center in El Paso, Texas, in a 10-round super-middleweight bout.

[38][39] In October 2016, it was announced that Chávez Jr. would be making a return on 10 December 2016 at the Monterrey Arena in Mexico against German boxer Dominik Britsch (32-2-1, 11 KOs).

Chávez Jr. picked up his 50th win of his career after defeating Britsch in a one-sided 10 round unanimous decision in front of a very small crowd in Mexico.

[48][49] Julio César Chávez spoke on 18 December about the ongoing negotiations saying Golden Boy were offering his son a small amount for the potential big PPV fight.

[50][51] On 24 December, Álvarez and his team gave Chávez a week to accept the terms, which included a purse of $7m, or he would consider other options.

According to Chávez Jr. the new demands included a weight limit set at 164.5 pounds and a $6 million base purse plus PPV revenue percentages.

[55][56][57] On 4 February, Golden Boy Promotions announced that the fight would take place at the T-Mobile Arena in Paradise, Nevada.

[66] This was the first boxing match to generate over 1 million PPV buys that didn't include Mayweather, Pacquiao or De La Hoya since 2002, which saw Lennox Lewis retain his heavyweight world titles against Mike Tyson.

[67] Following the loss to Alvarez, Chávez Jr. said he would be making a full comeback at 168 pounds in the super middleweight division.

[69] Chavez Jr. on 17 September, announced that he would fight at the full super middleweight limit of 168 pounds against former WBC champion Anthony Dirrell (30-1-1, 24 KOs) at The Forum in Los Angeles, California, on 11 November 2017.

[73] On 14 November 2017, fellow Mexican Alfredo Angulo (24-6, 20 KOs) was named as a possible opponent as both boxers being advised by Al Haymon.

[79] On 10 August 2019, Chavez finally made his return to the ring after not having boxed for 2 years and 3 months and knocked out unrecognized Colombian Evert Bravo (25-10-1 with 9/10 losses coming by KO) in the 1st round in front of a crowd of 6000 fans at the Antonio R. Márquez Stadium in San Juan de los Lagos, Jalisco.

He was scheduled to face Mario Abel Cazares on 25 September 2020, with the bout serving as part of the undercard for an exhibition match between Chávez' father and former four-weight world champion Jorge Arce.

The last knockdown prompted Minda's corner to stop the fight early, and earn Chávez Jr a TKO win.

[82] In March 2021, it was announced that Chávez Jr would face former UFC Middleweight Champion Anderson Silva on 19 June 2021.

[86] Chávez Jr was scheduled to face former UFC Welterweight title contender Darren Till, on the Jake Paul vs. Mike Tyson card on 20 July 2024 in a six round cruiserweight bout.

[88] A separate event took place on 20 July 2024 at the Jake Paul vs. Mike Perry card and Chávez Jr faced former UFC fighter Uriah Hall.

[91] On 3 February, Chávez Jr. revealed that he had hired hall of fame trainer Ignacio "Nacho Beristain" for the Álvarez fight.