Bradley had his first professional bout on August 20, 2004 knocking out Francisco Martinez in the second round. In his rise through the ranks, he won the WBC youth world welterweight and super lightweight crowns. He also beat future IBF lightweight champion Miguel Vazquez by a unanimous ten-round decision.
Bradley finally got his chance for a full world title when José Luis Castillo failed to make weight in a title eliminator for the WBC super lightweight belt. He then won the WBC super lightweight title by defeating British fighter Junior Witter in England. Bradley's bank account was down to $11 when he made the decision to go to England to fight Junior Witter. Bradley came into the fight a 6–1 underdog against Witter. During the fight, Bradley controlled most of the action, and dropped Witter in his corner during the 6th round. Though the fight was scored a close split decision for Bradley, most observers and analysts thought Bradley should have comfortably been given a unanimous decision verdict.
On April 4, 2009 Bradley fought Kendall Holt to unify his WBC and Holt's WBO titles. Bradley was dropped in the first round by a huge left hook and was badly hurt but regrouped and outboxed Holt for most of the fight, before being sent to the canvas again in the 12th round. Nonetheless, Bradley got up and finished the fight. He won the fight by unanimous decision and became the new WBO champion.
Several days after his unification bout with Holt, Bradley was stripped of his WBC junior welterweight title, because of failure to fight Devon Alexander, his mandatory challenger. As a result, the title became vacant and Alexander stopped Witter at the end of eight rounds to win the belt.
The Alexander-Witter fight was on the undercard of Bradley's August 1 fight with Nate Campbell in Bradley's hometown of Palm Springs. Campbell, a former lightweight champion, was coming up in weight after he failed to make the lightweight limit in his last fight. Bradley's fight with Campbell only lasted three rounds after Campbell chose not to continue when a cut formed over and behind his left eye. Bradley was awarded the TKO victory, but the verdict was later changed. A replay showed that the cut was caused by an accidental clash of heads. The rules state that if a fight is stopped by a cut caused by an accidental headbutt before the end of round four, it should be called a no contest. The California State Athletic Commission therefore changed the result.
On December 12, Bradley took on mandatory challenger and future light welterweight champion, Lamont Peterson. Bradley dominated the fight, knocking Peterson down in the third round and went on to win a lopsided unanimous decision.
In his HBO Debut, Bradley was scheduled to face Luis Abregu in a non title bout at welterweight. However, Bradley's promoter told ESPN.com that he had made a deal with Golden Boy Promotions to fight Interim title holder and knockout artist: Marcos "El Chino" Maidana, at the Agua Caliente Casino in Rancho Mirage, California, only a few miles from Bradley's hometown of Palm Springs. The fight was scheduled to take place on June 19, 2010 but was postponed after Maidana had suffered a back injury during training for the fight. As a result, the initial plan to move up in weight was made and the fight with Abregu was back on, scheduled for the Agua Caliente Casino, along with a set fight date of July 17, 2010. Although clearly out-sized, Bradley proved too quick and too skilled for the hard-hitting Abregu winning by unanimous decision, with the judges' scorecards reading 119–111, 118–112 and 117–113.
At the end of the fight, Bradley openly made a challenge to pound-for-pound king Manny Pacquiao, calling for him to "Come break down this wall." Bradley also called out Devon Alexander, Amir Khan and Marcos Maidana.
On January 29, 2011 Timothy Bradley defended his WBO junior welterweight title in a unification fight against fellow light welterweight title holder, WBC champion Devon Alexander, at the Silverdome Arena in Pontiac, Michigan. Bradley won via 10th round technical decision.
As stipulated in the contract of the fight against Devon Alexander, Bradley would be given a $1.3 million payday regardless of whomever he selected as his opponent for his next fight. While the public wanted Bradley to fight the then WBA light welterweight champion Amir Khan and unify the division, Bradley opted to not take the fight.
Timothy Bradley was stripped of his title as he refused to fight then World Boxing Association light welterweight champion Amir Khan. Many had speculated that Bradley was not satisfied with the $1.3 million to fight a boxer of Amir Khan's caliber, although this was Bradley highest pay day in his entire career so far. Also, he had admitted that it was too risky to fight Amir Khan, asking rhetorically on the American radio show Leave It In The Ring, "What if I lose then I am out the sweepstake to fight pound-for-pound-king Manny Pacquiao for 7.5 million dollars?" Bradley's refusal to take the fight led to a falling out between him and his promoter Gary Shaw. Subsequently, he was stripped of the WBC title due to inactivity.
Timothy Bradley joined Top Rank and made his debut for them on November 12, 2011 defending his WBO junior welterweight title against former lightweight titlist Joel Casamayor, 40, on the undercard of Pacquiao vs. Marquez III. Bradley won by TKO in the eighth round in making his case for a shot at Pacquiao.
Bradley fought Manny Pacquiao on June 9, 2012 for Pacquiao's WBO welterweight title. Bradley won a controversial victory over Pacquiao by way of split decision, with two of the judges scoring it 115–113 to Bradley and the other 115–113 to Pacquiao. The decision ended Pacquiao's 7-year undefeated streak and gave Bradley the title. According to Compubox, Pacquiao was ahead in punches landed, power punches landed, percentage of punches landed, and percentage of power punches landed. As a result of the controversial scoring, a special five-judge panel was created by World Boxing WBO President Francisco "Paco" Valcarcel to review the fight. All five judges of the panel reviewed a video of the bout and all 5 judges scored it in favor of Manny Pacquiao. Despite the panel's findings, WBO rules do not allow the decision to be overturned. The most the boxing body can do, according to Valcarcel, is to order a rematch.
Bradley won a close unanimous decision against Ruslan Provodnikov on March 16, 2013 for the WBO welterweight championship. Provodnikov was given the fight to serve as an easy target for Bradley, who was looking for a confidence booster after a controversial fight with Manny Pacquiao. Bradley came out on the attack early, fighting in an uncharacteristically aggressive fashion. Provodnikov made him pay, tagging him with hard shots in the first round, and staggering him in the second. Bradley said post-fight that he was concussed by a shot Provodnikov hit him with in the first round. Bradley boxed more conservatively as the fight wore on, winning most of the middle rounds. In the last round, Provodnikov again hurt Bradley badly and appeared ready to deliver a KO, but with time running out Bradley deliberately took a knee to get called for a knockdown. He was easily able to beat the count (which finished only seconds before the final bell) as a result and hung on to win the fight on points. Bradley was impressed by Provodnikov's power and said that "he's going to be a world champion someday."
Bradley's bout with Ring #3 ranked pound for pound, Ring #5 ranked junior lightweight and WBO junior welterweight champion Juan Manuel Márquez was held on October 12, 2013 at the Thomas & Mack Center in Las Vegas, Nevada. Bradley was awarded a split decision win, in a fight where he wobbled Márquez in the final round with a left uppercut en route to winning via split decision with scorecards of 116–112, 115–113 and 113–115.
Bradley gave Manny Pacquiao a rematch on April 12, 2014. Ironically, the second fight was closer than the first contest according to many pundits. Pacquiao pulled away on the scorecards in the second half of the fight winning with a unanimous decision (118–110, 116–112, 116–112), ending Bradley's undefeated streak.
Following his first career loss to Manny Pacquiao, Bradley fought former WBA welterweight interim champion Diego Chaves of Argentina, in Cosmopolitan of Las Vegas, Las Vegas, Nevada on December 13, 2014. The official scorecards led to a controversial split-draw (Julie Lederman 112–116 for Chaves, Burt A. Clements 115–113 for Bradley, while Craig Metcalfe 114–114 for an even). Harold Lederman, HBO's unofficial judge, had it 116–112 for Bradley and the Compubox statistics heavily favored a Bradley win as they stated he had connected with 225 of 572 punches versus the 152 of 570 blows Chaves connected with.
Bradley fought and beat the undefeated boxer Jessie Vargas on June 27, 2015 at StubHub Center, California, USA on HBO World Championship Boxing to capture the WBO Welterweight Interim title. He won the fight by unanimous decision.
On July 6, the WBO welterweight champion Floyd Mayweather was stripped of his title for failing to pay a $200,000 sanctioning fee for his bout with Manny Pacquiao and for not relinquishing his world titles in the Junior Middleweight division, as the WBO rules mandate that a champion of theirs can only hold titles in one division at a time. Therefore, Bradley was promoted to the full-time WBO welterweight champion.
ESPN reported on September 8, 2015 that Bradley would make the first defence of his WBO title against 29 year old former WBA lightweight champion Brandon Ríos (33-2-1, 24 KOs) on November 7 at the newly refurbished Thomas & Mack Center in Las Vegas. Bradley also headlined the last card to take place at the Thomas & Mack Center on October 12, 2013. Negotiations were on and off for the fight and nearly broke down completely in August. Due to Sadam Ali being Bradley's mandatory, the WBO stated they would not sanction the fight unless Top Rank made a deal with Ali's promoter Golden Boy, to negotiate a step-aside fee.
Bradley fought and beat former Lightweight champion to retain the WBO Welterweight title. He was trained by his new coach and TV analyst Teddy Atlas. Bradley won the fight by technical knockout in Round 9 at 2:48, after he put Ríos down with a body shot and followed it up with a barrage of punches, dropping Ríos again and prompting referee Tony Weeks to wave off the fight.
On December 30, 2015 Bob Arum announced that Manny Pacquiao (57-6-2, 38 KOs) would fight Bradley for the third time in what would be his last professional fight. The fight was set for April 9, 2016 at the MGM Grand Garden Arena in Las Vegas. It was reported that Pacquiao would earn $20 million and Bradley would earn $4 million from the fight. In front of 14,665, Pacquiao knocked Bradley down twice and outpointed him throughout the fight, winning by unanimous decision after all three judges scored the bout 116-110 in his favor. ESPN.com scored it for 117-109 also in favor of Pacquiao .Bradley was down once in round seven and again in round nine. In the post fight Bradley spoke about how patience was the key difference in the fight, "Manny was very strong in there. Very heavy punches. He was also very patient. I wasn't professional enough to stay patient myself, and I walked into shots." CompuBox statistics showed that Pacquiao landed 122 of 439 punches (28%), whereas Bradley connected on 99 of his 302 punches thrown (33%). Many experts, including both fighters called the rubber fight the best of their trilogy. The fight drew 400,000 buys on HBO PPV, generating $24million. This was considered a low number, as the main event's purses alone equalled $24 million. Pacquiao received a special version of the vacant WBO International title in recognition of his win
On July 27, 2017 Bradley stated he would announce his retirement. In a statement, referring to his fight against Ruslan Provodnikov, he said, “A few weeks after the fight, I was still affected by the damage that was done. My speech was a little bit off. I was slurring a little bit. But after about two months, I cleared up and I have my wits about me now.” On August 6, 2017 he officially announced his retirement from professional boxing after nearly 12 years in the sport. The announcement came when he posted the following on his Instagram page:
I hope to continue to allow boxing in my world through teaching, commentating and being a fan of a sport I love so dearly. And to you, the diehard fans, man, it's been one heck of a ride. The bumps, the bruises, the peaks, the valleys, the days I didn't want to get out of bed and the nights I couldn't sleep....So many occasions where my heart, mind and soul were tested but with every challenge there was hope and there was all of you...giving me the courage to fight another day and do what I loved to do. I can never find the words to convey how much I appreciate all of you and how truly humbled I am by the unconditional support the past 23 years, Thank you. Thank you for cheering me on when I didn't deserve it, loving me most when I needed it and for being my heartbeat to keep going day after day. I am the man I am today because of you all.
He finished with a record of 33 wins, 2 losses and 1 draw with 13 knockouts in his career.
Bradley was born in Palm Springs, California on August 29, 1983, and grew up in Cathedral City, California. He went to Cathedral City High School, along with future mixed martial artist and current UFC contender Cub Swanson. Prior to becoming a professional boxer, Bradley worked as a dishwasher and as a waiter. He married his high school friend, Monica Manzo, in 2010 and became an adoptive father to Manzo's two children, all together the couple have five children. In 2015, a Golden Palm Star on the Palm Springs, California, Walk of Stars was dedicated to him.
Bradley was on a vegan diet for his fights from 2008 onwards. He said that he first tried the vegan diet while preparing for his fight against Junior Witter. In this fight, which Bradley won by split decision, Witter was knocked down in 6th from overhand right. After the fight Bradley was proud of the results and maintained his diet. He added that when he was on the vegan diet, he felt superior over any athlete who gets in the ring because it gave him energy, helped with his reflexes and balance. This diet was abandoned prior to the Jessie Vargas fight in 2015.