"No one else can put their band in sketches and have them score," Fallon told me in an interview at NBC10. "They're talented, talented people. When I first hired them, they were a band, a great band. Now, they're friends. They're family."
The Roots, as you've probably heard, will be moving with Fallon to 11:35 p.m., when he takes over "The Tonight Show" from Jay Leno on Feb. 17 and brings the show back to New York.
"That was the first question I asked. 'Has anyone talked to The Roots about this? Are they down?' " Fallon said. "They're so excited. Deal's done, contract's signed, they're all cool."
Cool might not be the word to describe Fallon, whose enthusiasms are varied and vocal, but he knows his priorities.
He recently turned 39 and has had a couple of major life changes in recent months, but it was the arrival of his and wife, Nancy's, new daughter, Winnie, born in July with the help of a gestational carrier, that "was the big emotional moment for me," he said.
"Because we've been trying for a long time, my wife and I," he said. "It's not easy to have children, clearly, for some men and women. So we struggled for about five years, trying every single thing. And it's just draining and you've just got to keep your hopes up."
Asked which was most likely to keep him awake - the prospect of "Tonight" or his new daughter - Fallon quipped, "Thank God for sleeping pills."
At night, "I'm constantly thinking, 'Is the baby all right? Is she crying?' We have the monitor and all that stuff and then I'm like, 'Does Justin Timberlake want to do a bit? We can do that singing bit, we can do - Let's go back to the baby. Is the baby crying? Is the baby fine? When should I change her?' I mean you're constantly thinking about a hundred things. My brain always is. I've never been diagnosed for ADD, but I'm assuming I'm close."
No Leno replay
What he's not worrying about, he insisted, is a repeat of what happened to Conan O'Brien when he took over "The Tonight Show," only to have Leno return, a situation even messier than the shift from Johnny Carson to Leno that led David Letterman to quit "Late Night" to join CBS.
"It feels different to me. It is different," Fallon said. "When [Leno] felt like it was the right time, he called me and said, 'I think it's the right time. And I think you're the guy who should do it. You're the closest to what Johnny was doing.' Which was the ultimate compliment," said Fallon, who works - and will stay - in the 30 Rockefeller Center studio where Carson did "Tonight" before it moved west in 1972.
Not that he ever expected to follow Carson anywhere.
"I never thought that was a job when I was growing up," Fallon said. "I just assumed, that's Johnny Carson, that's his thing. He lives forever.
" 'Saturday Night Live' was my big goal. I did that, it was amazing," and as he was leaving, executive producer Lorne Michaels told him that O'Brien had " 'just signed this thing that he's going to take over 'The Tonight Show' in like . . . five years. Did you ever think of doing a talk show?'
"I was thinking I was going to try movies, but that [hosting] could be kind of fun. And then in five years, Lorne called me and said, 'Hey, you remember I asked you that five years ago? Still interested? Would you want to do it?' "
The name game
One thing Fallon may have going for him, I suggested, is a first name that begins with "J," just like the three longest-running "Tonight Show" hosts: Carson, Leno and Jack Paar.
But, he countered, he also shares a first name with ABC's late-night host, Jimmy Kimmel.
"It's tough . . . People stop me on the street. They go, 'Jimmy Kimmel! Oh my God! Can I get your autograph?' "
When I mentioned that his announcer, Steve Higgins, looks like early "Tonight Show" host Steve Allen, Fallon perked up. "I love that. Steven Allen. Gosh. I mean, half my audience would not even know who Steve Allen is, which is sad. I wish that Steve Allen were around still, because I think that he would love our show.
"He was the first guy, before Letterman, to sit in a giant bowl and make himself a banana split, and they put ice cream and chocolate syrup on Steve Allen."
Allen, though, never played Egg Russian Roulette with Tom Cruise or Edward Norton.
How did he get Cruise to play?
"I said, 'Can I pitch him this game? It's called Egg Russian Roulette, where we have a dozen eggs and three of them are raw, the rest are hard-boiled. And the only way you're going to know is, we have to crack them on our heads. And they [his publicists] go, 'Well, why don't you pitch that to him?'
"So I walked in and I said, 'Hey, we're doing this game where we crack eggs on our head.' He goes, 'Love it. Is it rigged?'
"I go, 'It's not rigged. No, I would never rig a game.' "
Cruise's response: " 'Let's do it, man.' So we're sitting there and . . . the game is the first person who cracks two raw eggs on their head loses. I'm not kidding, the first two eggs Tom Cruise chooses are raw. So he loses the game immediately. There's nothing on me. My suit is completely clean," Fallon said, laughing.
"I go, 'Thanks for being here.' He's like, 'You jackass! Why would I ever come back?' But he's a friend of the show now."
It's hard to imagine Fallon getting bigger guests for "Tonight" than he does for "Late Night," where he's sung with Bruce Springsteen and left movie stars covered in egg yolk.
The studio's getting a makeover - more seats, better acoustics - but "the show's not going to change," Fallon vowed.
"In our head, we're doing 'The Tonight Show.' We have been for five years. So I'm in the on-deck circle . . . I'm ready to swing."
On Twitter: @elgray