Lesnar later departed NJPW and continued to be promoted as the IWGP Heavyweight Champion in the IGF before taking a hiatus from wrestling to pursue a career in mixed martial arts (MMA).

[1][24] After two years at Bismarck State College, Lesnar transferred to the University of Minnesota on a wrestling scholarship, where he was roommates with future WWE colleague Shelton Benjamin, who was also his assistant coach.

[46] At WrestleMania, Lesnar defeated Angle to win his second WWE Championship; during the match, he botched a shooting star press (a move he had used numerous times in OVW) and landed on his head and neck, resulting in a concussion.

[53] On the September 18 episode of SmackDown!, Lesnar defeated Angle in an Iron Man match to win his third WWE Championship[54] by a final score of five to four, thus ending their long-standing feud.

Lesnar chose Big Show as his first teammate, with Heyman adding a returning Nathan Jones and a debuting Matt Morgan to bring the team number to four.

[66] After WrestleMania XX, Lesnar left WWE, citing burnout, injuries, poor creative decisions, an addiction to alcohol and painkillers and the rigorous travel schedule as reasons for his departure.

Angle made him tap out to the ankle lock to win the IWGP Heavyweight Championship as recognized by IGF and Total Nonstop Action Wrestling (TNA).

[105] On the December 30 episode of Raw, Lesnar returned with Heyman to challenge the winner of the upcoming WWE World Heavyweight Championship match between Randy Orton and John Cena at the Royal Rumble.

[109] On the February 24 episode of Raw, Heyman stated that Lesnar had requested a match for the WWE World Heavyweight Championship at WrestleMania XXX, but received an open contract to face anyone else of his choosing instead.

[128] On the January 11, 2016, episode of Raw, Lesnar returned, attacking The New Day, The League of Nations (Sheamus, King Barrett, Rusev and Alberto Del Rio) and Kevin Owens, before performing an F-5 on Roman Reigns.

[155] On the October 17 episode of Raw, Goldberg returned to WWE after a twelve-year absence and accepted Lesnar's request for a fight with their match later scheduled for Survivor Series.

[163] Lesnar returned on the January 16 episode of Raw to confront other Royal Rumble participants, attacking Sami Zayn, Seth Rollins, and Roman Reigns.

On the July 31 episode of Raw, Lesnar was scheduled to defend his title in a fatal four-way match at SummerSlam against Samoa Joe, Roman Reigns and Braun Strowman.

[187] The next night on Raw, Acting General Manager Baron Corbin scheduled Reigns to defend the Universal Championship in a triple threat match against Lesnar and Strowman at Crown Jewel on November 2.

[218] On the following episode of SmackDown, he started a locker room-clearing brawl with Reigns, resulting in an indefinite suspension by on-air authority figure Adam Pearce, whom Lesnar attacked.

[222] At Day 1 on January 1, 2022, Lesnar won his sixth WWE Championship, defeating Bobby Lashley, Kevin Owens, Seth Rollins, and defending champion Big E, who he pinned.

[228] On the June 17 episode of SmackDown, Lesnar once again returned to confront and attack Reigns after he successfully defended the Undisputed WWE Universal Championship against Riddle, renewing their rivalry.

[231] On the October 10 episode of Raw, Lesnar made a surprise return, attacking United States Champion Bobby Lashley and injuring his shoulder before his scheduled title defense against Seth "Freakin" Rollins, resuming their feud.

[240] On the April 3, 2023, episode of Raw, the day after Night 2 of WrestleMania 39, Triple H introduced Undisputed WWE Universal Champion Roman Reigns, accompanied by Paul Heyman and Solo Sikoa.

[270]Lesnar had a great showing at the NFL Scouting Combine, but on April 17, a minivan collided with his motorbike and he suffered a broken jaw and left hand, a bruised pelvis and a pulled groin.

[276][274] Lesnar received an invitation to play as a representative for the Vikings in NFL Europa, but declined due to his desire to stay in the United States with his family.

[267] On April 29, 2006, after the final match of the K-1 World Grand Prix 2006 in Las Vegas, Lesnar stated his intent to join K-1's mixed martial arts league, Hero's.

[290] He denied Couture's takedown attempts and outstruck him on the feet, eventually knocking him down and landing ground and pound until he was awarded the technical knockout and UFC Heavyweight Championship.

[299] After further diagnosis, Lesnar underwent surgery on November 16 to close a perforation in his intestine that had been leaking fecal matter into his abdomen, causing pain, abscesses and overtaxing his immune system to the point that he contracted mononucleosis.

In the next round, Carwin was noticeably fatigued and Lesnar scored a takedown, attained full mount, then move into side-control and finish the fight with an arm-triangle choke.

[314] Lesnar attempted to takedown Overeem but was unable and ate heavy body shots to his surgically repaired stomach, eventually being finished with a liver kick and punches.

[345] Lesnar co-wrote an autobiography with Paul Heyman, titled Death Clutch: My Story of Determination, Domination, and Survival, which was published by William Morrow and Company in 2011.

[360] Lesnar developed addictions to alcohol and painkillers during his first run in WWE, later claiming that he would drink a bottle of vodka per day and take hundreds of Vicodin pills per month to manage the pain caused by wear and tear on his body.

[362] Lesnar had previously signed a non-compete clause in order to be released from his contract with WWE, which prohibited him from working for any other professional wrestling companies before June 2010.

[367][368] On January 14, 2006, Judge Christopher Droney stated that unless WWE gave him a good argument between then and the 25th, he would rule in favor of Lesnar, giving him a summary judgment.