After college, he worked as a bouncer and entered mixed martial arts at age 20, after a friend suggested it due to his wrestling background.
After his first professional loss, Johnson then faced Tom Speer at UFC Fight Night: Florian vs.
[19] Johnson fought Luigi Fioravanti at UFC Fight Night: Lauzon vs. Stephens on February 7, 2009.
[20] Johnson was scheduled to fight Matt Brown at the TUF 9 Finale, but had to pull out after suffering a knee injury.
Johnson knocked out Yoshida 41 seconds into the first round, but was not eligible for the Knockout of the Night bonus due to missing weight.
[21] After his fight with Yoshida, Johnson made a quick turnaround and faced Josh Koscheck on November 21, 2009, at UFC 106.
Johnson was expected to face John Howard on March 21, 2010, at UFC LIVE: Vera vs. Jones,[23] but had to pull out due to suffering a knee injury in training.
[26] Johnson used superior wrestling and controlled Hardy to a unanimous decision victory, dropping him with a left head kick in the first round.
Johnson was expected to face Nate Marquardt in what would have been his first main event on June 26, 2011, at UFC on Versus 4 but was forced out of the bout with an injury and replaced by Rick Story.
[28] For his next fight, Johnson attempted to move up to middleweight to face Vitor Belfort on January 14, 2012, at UFC 142.
[29] Leading up to the UFC 142 weigh-ins, doctors advised Johnson to terminate his weight cut and rehydrate.
On fight day, Johnson officially weighed in at 204.2 lb, and Belfort won via first round submission.
[43] Johnson next faced Antônio Rogério Nogueira in the co-main event on July 26, 2014, at UFC on Fox 12.
[49] Due to the suspicion, UFC released a statement that Johnson was being indefinitely suspended until the case was investigated.
[51] Johnson fought Alexander Gustafsson on January 24, 2015, at UFC on Fox 14 with the promise that the winner would earn a title shot against Jon Jones.
[52] Johnson won the one-sided bout via TKO in the first round, becoming the first to stop Gustafsson due to strikes.
[55] However, on April 28, it was announced that Jones had been stripped of the UFC Light heavyweight title and suspended indefinitely due to a felony hit-and-run charge.
[63] Johnson was expected to face Glover Teixeira on July 23, 2016, at UFC on Fox 20, but was pulled from the card due to undisclosed reasons.
[70] Johnson decided to use his wrestling as his main offense, a decision which frustrated his corner, and led to him becoming fatigued and losing the fight via rear naked choke submission in the second round.
[71][72] In 2017, Johnson switched to Combat Sports, an open gym club, and CSMMA after Blackzilians ceased operations across the Florida area.
[73] In August 2019, 2 years after initially announcing his retirement, Johnson confirmed that he would be re-entering the USADA testing pool.
[76] On December 9, 2020, it was announced that Johnson had parted ways with the UFC and had signed a multi-fight contract with Bellator MMA.
[77] On February 9, 2021, it was announced that Johnson would be participating in the Bellator Light Heavyweight World Grand Prix Tournament.
[79] On April 29, it was announced that Yoel had failed his pre-fight medical exam and the bout was scrapped and Romero was removed from the tournament.
[82] On September 18, it was announced that Anthony Johnson was forced to pull out of the bout and the tournament due to an unspecified illness.
In early 2019, Johnson was appointed as the head of fighter relations for Bare Knuckle Fighting Championship.
[88] The case was ultimately dismissed, with the charges against Johnson being dropped when he reached a joint agreement with the prosecutors by agreeing to attend an anger management course.