McGregor made history at UFC 205 on Saturday night by becoming the first UFC fighter to simultaneously hold world titles in two different weight divisions.
Triple H, the executive vice president of talent, live events and creative for WWE, was ringside at Madison Square Garden to witness the Irishman's second-round knockout of Eddie Alvarez.
"He could come over, he's got it all, man," Triple H told the Daily Telegraph's Gareth A. Davies. "He's got the personality, the skills, the talk. He's an entertainer, for sure.
"What does he walk around at? 180 pounds? I have smaller guys now in the WWE. We have 200-pound guys who are stars. You don't need to be 300 pounds any more.
"He could do just as well as Floyd Mayweather when he fought the Big Show. That really worked. Conor could do it for sure."
Undefeated boxer Mayweather won that bout at Wrestlemania XXIV in 2008, in front of more than 74,000 people at the Florida Citrus Bowl. The event broke the record for the highest-grossing pay-per-view in WWE history at the time.
There has long been speculation that McGregor, who added the lightweight title to his featherweight belt in New York, could make a similar crossover appearance at the WWE's biggest event of the year.
The 28-year-old was asked earlier this summer on a conference call before his UFC 202 rematch with Nate Diaz whether he would consider shifting to WWE in the future, like Brock Lesnar before him.
"There's some Dons in that wrestling game," McGregor said. "The McMahons are Dons. Triple H is a Don. The Rock is a Don. But the rest of them are p-----s. I haven't thought about that, to be honest. It's a little more show business and this is the fight business."