The times, they are a changin’, as Bob Dylan famously sang. Though most would sadly agree that the change has been pretty bad and is getting worse by the day, for Jimmy Fallon it’s all good.

For Fallon, change has come at precisely the right time – 12:30 a.m., to be exact, Monday to Friday, on NBC, where he has held court since March 2 as the new host of "Late Night," the venerable talk show that made stars out of David Letterman and the newly departed Conan O’Brien.

Fallon, 34, best known up until now as a member of the cast of "Saturday Night Live" from 1998-2004, is more than ready to embrace the high-profile challenge of stepping into O’Brien’s very successful shoes. The career shift came at a perfect time, as Fallon tried movies to mixed success and was eager to return to his standup roots.

“I’m putting everything, everything I got into this. And I really want to be around for a long time so I’m really focused,” Fallon said during a recent interview. 

Of course, hosting a top entertainment show comes with some cool fringe benefits, like getting to meet childhood idols. Day One of the show brought a big favorite into the studio at Rockefeller Plaza – Van Morrison.

“I … grew up an Irish kid and, you know, he comes on your iPod in your brain when you’re born. He’s just like — he’s one of my favorites of all times.  The fact we have Van Morrison on alone should be a shout-out to all my Irish friends going, ‘All right,’” Fallon laughs.

The luck of the Irish is exactly what Fallon is hoping for as his show takes on the challenges of carving its own place in the late night landscape.  And he’s surely entitled to a large helping of it, as he’s a proud Irishman through and through.

“It’s really, really great — I was very happy to be raised Irish,” says Fallon.  “We grew up totally having a party — we were the Irish family. Across the street from us we had a great Italian family. Between the both of us there’d be a party every weekend.”

The parties first got underway in Brooklyn, where Fallon was born in 1974 and raised for the early part of his youth, until he and his folks and sister Gloria left the city for upstate Saugerties.

“My dad fixed machines at IBM in Brooklyn and then moved upstate. And my mom, she had a bunch of jobs here and there but ended up being the best mom; she raised me and my sister,” Fallon said.

“I have a lot of relatives that are tall, red-faced, white hair people. My parents are both Irish; my dad’s Irish and German and my mom’s Irish and Norwegian.

“Cork is where I think we’re from. I’ve got to do the research. I never went into ancestry.com but I should have done that.”

Fallon’s first trip to Ireland came courtesy of his sister, who was studying on a scholarship at a university in London.  Gloria won an essay contest, and her reward was to bring a friend over to visit for a week.  Her preferred pal turned out to be little brother Jimmy, and the two of them skipped over to Ireland.

“I got my first credit card and we went to Ireland and we went to Kinsale, and I just was blown away by how nice and gorgeous people were. And, yeah, I mean I love it so much,” he says, adding that he’s been back there “numerous, numerous” times since.

His affinity for his Irish roots isn’t surprising, given that the Fallon family home was devoid of drama and always full of music and laughter and fun.

“It’s that Irish personality where, you know, I wasn’t one of those people that needed to kiss the Blarney Stone. I was kind of always talking. I came from a family of just entertaining people. I mean, both sides of my family are really, really funny entertaining people,” he says.

“They would have parties and they would sing, you know, have a microphone set up with a reel to reel and some speakers and just — everyone would sing songs. Even though we weren’t famous, you know, we were a performing family pretty much.”

Perhaps it’s too strong to say that Fallon’s career was at a crossroads when the opportunity to take the helm from Conan O’Brien presented itself.  But he was ready for a new challenge, and they don’t come much bigger than fronting a successful and profitable network late night show.

“You know, I got my shot at the movies. I love standup live and I didn’t know what I wanted to do. I wanted to try movies and so I gave my shot at the movies. I had two shots and I didn’t really do it,” Fallon says.

The notion of Fallon one day replacing O’Brien — who grew restless in his "Late Night" role to such an extent that NBC inked him to a new deal in 2004 that guaranteed he’d take over from Leno this year — was always a definite possibility in the mind of Lorne Michaels, the creator of SNL who also produces "Late Night."

“And so then 2009 rolls around, like 2008 actually, and then [Lorne] called me and said, ‘Hey remember that thing we were talking about five years ago’ … and I was like, ‘All right, I guess,” Fallon recalls.

It’s been all go ever since the official announcement of Fallon’s ascendancy was made last May. "Late Night With Jimmy Fallon" aims to stand out from the crowded pack of TV talk shows by being as interactive as possible with its audience, whether it’s during the program’s actual broadcast or its Web site, www.latenightwithjimmyfallon.com, which contains videos and full show episodes, as well as continuously updated posts from Fallon.

“We’re going to kind of make our show and give our fans as many ways possible, different ways to enjoy our show.  And the fun thing is if it doesn’t work it’s still fun to experiment and try stuff; it’s 12:30 at night.  I mean, honestly I just want to kind of keep people awake. Or at least give you one joke to go to bed with," says Fallon.

Fallon’s first week brought A-list guests like Robert De Niro, Justin Timberlake, Cameron Diaz, Tina Fey and, of course, Van Morrison. The ratings for the first broadcast on Monday, March 2 were stellar, with a 35 percent bump in viewership that wasn’t surprising considering the curiosity factor for such a hyped debut.

Critically speaking Fallon’s Late Night was both praised and skewered, also not shocking given the growing pains associated with any new broadcast. (O’Brien’s first couple of years in the chair were so rough that NBC committed to renewing his show only in multi-week timeframes.)

Now that the first week jitters are over, Fallon and his team will get down to the business of building a show that will carry on the storied "Late Night" tradition. Fallon spent several months on the road fine-tuning his stand-up skills in anticipation of his nightly monologue, and he’ll continue to schedule engagements across the country on weekends.

Fallon will undoubtedly be in his element for the St. Patrick’s Day airing of Late Night.  He promises to have a “St. Paddy something” on the show, and to even travel to Ireland in the future for broadcasts. (O’Brien was also a vocal proponent of his Irish heritage, and traveled to Ireland in search of his roots for some very funny "Late Night" broadcasts.)

“I love it so much. I totally want to go there and do a show from there,” he says. “And I actually know like a lot of Microsoft is in Ireland, so maybe we could do some techy something over there as well.”

And in the unlikely event that all goes wrong at "Late Night," Fallon could undoubtedly pursue a career impersonating Van Morrison, which he did quite successfully during his time on "Saturday Night Live."

“I can almost guarantee you he has no idea who I am. I could almost guarantee that to you,” Fallon said when asked if he’s shown the impression to Morrison when the two met.

“But I respect him, I love him and I could sing any song backup if he needs me.”