By January 2000, Triple H had dubbed himself "The Game", implying that he was on top of the wrestling world (as in not merely the "best in the game", but that he was in fact "the game") and was nicknamed "The Cerebral Assassin" by Jim Ross. On the January 3 episode of Raw Is War, Triple H defeated Big Show to win his third WWF championship.
Triple H feuded with Mick Foley in early 2000. They both fought at the Royal Rumble in a Street Fight Match for the WWF Championship, which Triple H won after performing two Pedigrees on Foley. The feud ended at No Way Out in a Hell in a Cell, where Triple H retained the title and forced Foley to retire. Triple H pinned The Rock at WrestleMania 2000 to retain the title, but lost it at Backlash to The Rock, thus ending his reign at 118 days. He regained it three weeks later, in an Iron Man match at Judgment Day, only to lose it back to The Rock at King of the Ring. Triple H then entered a storyline with Chris Jericho, who upset Triple H by defeating him for the WWF Championship on the April 17 episode of Raw Is War before the title was returned to Triple H because of a fast count made by referee Earl Hebner, and Jericho's reign is not being recognized. Their feud culminated in a Last Man Standing match at Fully Loaded which was won by Triple H. Afterwards, Triple H entered a feud with Kurt Angle, initially over the WWF Championship, but then as a love triangle between himself, Angle, and Stephanie. Both Triple H and Angle wrestled for the WWF Championship against The Rock at SummerSlam, but The Rock retained the title after Angle received a legit concussion during a botched Pedigree on a commentary table by Triple H. The feud culminated at Unforgiven, where Triple H defeated Angle with a Pedigree after a low blow from McMahon.
After a brief run as a face that saw him defeating Chris Benoit at No Mercy, Triple H reverted to his heel persona and restarted his feud with Stone Cold Steve Austin when it emerged that Triple H had paid off Rikishi to run down Austin at Survivor Series, causing him to take a year off. While in the storyline Triple H said he had done it in order to shield Austin from the WWF Championship and end his career, in reality Austin's previous neck injuries started bothering him again, forcing him to have surgery. In November 2000, Triple H and Austin had a match at Survivor Series that ended when Triple H tried to trick Austin into coming into the parking lot to run him over again, only to have Austin lift his car up with a forklift and flip the car onto its roof 10 feet high. Triple H returned a few weeks later to attack Austin, and their feud continued into 2001 and ended in a Three Stages of Hell match in which Triple H defeated Austin. In 2001, Triple H also feuded with The Undertaker, who defeated him at WrestleMania X-Seven. The night after WrestleMania, Triple H interfered in a steel cage match between Austin (who had just won the WWF Championship) and The Rock where he joined forces with Austin and double teamed on The Rock, forming a tag team called The Two-Man Power Trip. Triple H then defeated Chris Jericho for his third Intercontinental Championship on the April 5 SmackDown!, and won it for a fourth time two weeks later by defeating Jeff Hardy. Triple H then became a world tag team champion by winning the WWF Tag Team Championship for the first time at Backlash when he and Austin defeated Kane and The Undertaker in a "Winner Take All" tag team match. As Triple H was still Intercontinental Champion, the win made him a double champion. In doing so, Triple H became the 7th Triple Crown winner and 2nd Grand Slam winner in WWE history.