(CNN) -- To thunderous applause and with a Cheshire cat grin, Jimmy Fallon walked on to the stage at the NBC Studio in New York Monday night -- the new host in the old home of the "Tonight Show."
"I am Jimmy Fallon and I will be your host -- for now," he said, a pointed reference to the exit-enter-exit history of the last host, Jay Leno.
His first joke out of the way, he spent the next few minutes introducing himself to the audience -- his childhood, his family, his career. He was pretty subdued through it all.
But then when the formalities were out of the way, he re-entered the show through the gigantic blue curtains -- the ever-hip Roots playing him in -- and started his show proper: the usual monologue and his usual over-eager but gracious self.
The laughs came easy.
And even before the new show's first guests appeared -- Will Smith and U2 -- a parade of celebrities walked up and dumped money on Fallon's desk.
"To my buddy who said that I'd never be the host of 'The Tonight Show,' and you know who you are," Fallon said, "you owe me a hundred bucks, buddy."
And out came Lady Gaga, Kim Kardashian, Rudy Guliani, Mike Tyson and many others, slapping down bills.
During the rest of the show, Fallon pulled out old bits with fresh takes -- such as an evolution of hip-hop dancing with Will Smith and 'Late Night Superlatives.'
The challenge now
With Fallon at the helm, the show moves back to New York for the first time since then-host Johnny Carson took it to Los Angeles in 1972.
For the rest of the week, the star power will burn equally bright.
Fallon's guests will include Jerry Seinfeld, Justin Timberlake and Michelle Obama.
The real challenge will be next week, and the next month, and the next year.
For most of his 22 years, Fallon's predecessor, Jay Leno, sat at the top of the late night talk show totem pole.
Sure, Leno was critically panned for his milquetoast interviews and his predictable jokes. But the masses loved him.
How will Fallon fare?
That's the big question.
For one thing, the late night landscape has changed. The hosts -- like Conan O' Brien and Jimmy Kimmel -- skew younger. And with Fallon, NBC hopes the audience will too.
While one-time host Johnny Carson has been the template all future hosts emulated, Fallon says he will fashion his stint after a different host: The original host, Steve Allen.
A freewheeling hodgepodge
Allen's was a free-wheeling hodgepodge of chat, skits, piano-playing, ad-libbing, man-on-the-street interviews and loopy stunts.
Fallon is a capable guitarist and musical mimic who has done dead-on parodies of Bruce Springsteen and Neil Young, among others. Bits with guests such as Michelle Obama and Justin Timberlake have gotten millions of views online, and segments such as "Slow Jam the News" have some of the whimsical quality that Allen was fond of.
Monday night's show ended with a new shareworthy moment: U2 and The Roots playing a goosebump-inducing, stripped-down version of "Ordinary Love."
CNN's Todd Leopold and Emma Lacey-Bordeaux contributed to this report.