Seth Meyers is the oldest, most experienced and most hostlike comedian to take the reins of NBC’s three-decade-old “Late Night.”

But starting Monday night, when he walks out into his shiny new studio at 30 Rockefeller Plaza, about 20 yards down the hall from where he has worked for the past 13 years on “Saturday Night Live,” the only thing that will matter is whether Mr. Meyers will be as funny as the three men who preceded him: David Letterman, Conan O’Brien and Jimmy Fallon.

“You can’t worry about it until it’s time to worry about it,” Mr. Meyers said, sitting in his unprepossessing office at 30 Rock. He acknowledged the daunting track record he will be following: Each of the previous three hosts graduated from successful runs in the 12:35 a.m. slot of “Late Night” to the big time of 11:35 p.m. shows on a network.

“I’m really looking forward to mid-March,” Mr. Meyers said. “When we’ve been on three weeks, it will be like looking at an ultrasound: Oh, I see its hand! Whereas right now we’ve got a heartbeat, but that’s all we’ve got.”