CM Punk's career began in 1999 in various independent scenes, most notably in Ring of Honor where he won the ROH World Championship once. In 2005, he joined WWE, where he held the World Heavyweight Championship three times, the WWE Championship twice, and the ECW Championship, Intercontinental Championship, and World Tag Team Championship once each, making him the nineteenth wrestler to complete the WWE Championship.

Triple Crown as well as the fastest to reach this milestone. He is also a two-time Money in the Bank winner, making him the only wrestler capable of earning this accolade twice in a row. His second reign as WWE Champion, which lasted 434 days, is the sixth longest in the history of the title. In 2021 he returns to wrestling by signing with AEW, winning the AEW World Championship twice.

He also pursued a short and ill-fated career in mixed martial arts via a contract with the Ultimate Fighting Championship. On September 10, 2016, after almost two years of training, he made his debut by being defeated by Mickey Gall in the first round by submission in 2 minutes and 14 seconds. On June 9, 2018, he also lost his second and final match against Mike Jackson in the third round by unanimous decision.