Lesnar wrestled professionally forWorld Wrestling Entertainment from 2002 to 2004. When he was in the WWE, he won theWWE Championship three times, theKing of the Ring tournament in 2002 and theRoyal Rumble in 2003. He left the WWE in 2004 and travelled to Japan to wrestle forNew Japan Pro Wrestling. While in Japan he won the IWGP Heavyweight Championship. Lesnar retired from professional wrestling to pursue a career in theUFC.
Lesnar made his return to WWE on April 2, 2012, delivering his finishing move the F5 toJohn Cena.[12] He began a feud withTriple H and faced him atSummerSlam on August 19, 2012 and won by submission and broke Triple H's arm. He released a tout and said that he was quitting the WWE because he had conquered everything in the WWE.[13]
He returned to the WWE again on January 28, 2013 and delivered an F5 toVince McMahon as McMahon was about to firePaul Heyman. The F5 resulted in McMahon's pelvis breaking.[14]
He fought in the UFC from 2008 to 2011, winning the UFC Heavyweight Championship before retiring from the UFC after losing his last match againstAlistair Overeem atUFC 141.[15]
AtUFC 200, Lesnar would come out of retirement. He represented Canada during the fight and would defeatMark Hunt by unanimous decision and recieved $2.5 million.[16] The win would later be turned into a no contest and he would be suspended after USADA tests revealedclomifene in his system.[17] Lesnar never paid the fine and retired afterwards.[18][19]