#6 CM Punk (WWE title reign: 434 days)
CM Punk's "Summer of Punk" kicked off with his legendary Pipebomb promo on WWE RAW in mid-2011. He spent the next several months in the main event scene alongside John Cena and Alberto Del Rio. Punk met Del Rio in a WWE title match at Survivor Series 2011.
He won the match to start one of the most impressive WWE title runs in history. Punk held the belt for the entirety of 2012 and finally lost it to The Rock at Royal Rumble 2013, ending his run at 434 days.
Corey Graves deleted his Tweet! More details HERE.
#5 Brock Lesnar (Universal title reign: 503 days)
Brock Lesnar met Goldberg in one of the main events of WrestleMania 33, with the Universal title on the line. The latter had defeated Kevin Owens mere days ago to win the belt. The match didn't last long and Lesnar defeated Goldberg for the first time in his career to become Universal Champion.
The Beast Incarnate's win kicked off a dominant Universal title reign that saw him put down the likes of Roman Reigns, Braun Strowman, and Samoa Joe. He finally lost the title to Reigns at SummerSlam 2018. Lesnar's Universal title run lasted 503 days.