The noisy green room of Jimmy Kimmel's talk show in Hollywood was crawling with the show's thirtysomething writers, who stole occasional glances at the monitors as the 45-year-old comic joked with a woman in the studio audience.

A few minutes later, Kimmel's former intern Carson Daly, now a friendly rival in the late-night TV wars, swung by for an on-camera visit. With ABC moving "Jimmy Kimmel Live" to an 11:35 p.m. time slot tomorrow, displacing the venerable "Nightline," Daly offered his host a prediction: "Now you're going to become probably the most powerful man in television."

ABC can only hope. The Disney-owned network and its rivals NBC and CBS are looking to win over the next generation of late-night TV viewers, and by moving Kimmel now, ABC is looking to put its man in the pole position.

For NBC's Jay Leno and David Letterman of CBS, the final sign-off is drawing nearer. Both are sixtysomething baby boomers who picked up the torch of NBC's Johnny Carson, whose "Tonight Show" ruled over late night for several decades.

But the type of talk show Carson presided over - a splashy party with a long monologue, skits and a big band - is slowly getting downsized. Think of Comedy Central's "Daily Show With Jon Stewart" and "The Colbert Report," which have become smash successes with a host and stripped-down comedy bits.

Late night's new paradigm, experts say, is tech-savvy, younger-skewing and much cheaper. That fits an age in which many viewers are forgoing watching an entire program at its scheduled time, opting instead to watch a few minutes on their phones or tablets the next day.

With his frequent YouTube videos, ragged skits featuring family members and interactive stunts such as tongue-in-cheek National Facebook Unfriend Day, Kimmel's show is tailored for this new era.

"Leno and Letterman have been doing this for a long, long time," said Gary Carr, senior vice president and executive director of national broadcast for ad firm TargetCast.

"You know they're not going to be doing it forever. Eventually they'll be gone. Kimmel is the young guy; he'll be around another 20 years," Carr added. "ABC figures, 'What the heck, let's move him up now, when people can get used to him.'"

Although late night isn't the gold mine it once was, the financial stakes for ABC and the other broadcast networks remain significant - more than a half-billion dollars in annual ad revenues are in play, according to Jon Swallen, chief research officer at Kantar Media, an ad-tracking and consulting firm.

The programs are also vital pistons in the high-revving Hollywood publicity machine. They function as breezy, inviting platforms for networks to promote their own schedules and stars. And often the late-night perch bestows a "halo effect" upon their frontmen, who are tapped to host awards shows.

Kimmel, a baby-faced comic veteran and a slightly world-weary demeanor, has been promoted with increasing fervor by ABC. Perhaps not coincidentally, he's also taken on a higher profile - hosting the White House Correspondents' Dinner in April and the Primetime Emmy Awards in September.

Kimmel is trying to take the promotion in stride, admitting that it's a lot easier to become a late-night star than it was when his idol Letterman crashed into the pop culture firmament 30 years ago with Stupid Pet Tricks and other inversions of typical talk-show fare.

"The reality is, I wouldn't be on if the late-night landscape wasn't crowded," Kimmel said before rehearsal at his studio recently. "I'm glad it's crowded. I'd be sitting home watching it on television if it weren't."

The bosses haven't pressured him to tone down his material for the earlier time period. "They said, 'We want you to just do what you're doing,'" he said. "I was very happy to hear that."

Kimmel's ratings are virtually assured an increase. Approximately 15 percent more viewers have their TV sets turned on at 11:35 p.m. than at 12:05 a.m., when Kimmel currently starts his show. He will need every viewer he can get, since "Jimmy Kimmel Live" currently averages 1.9 million total viewers, according to Nielsen.

That's only a little more than half what "Tonight" gets. Letterman's "Late Show" delivers 3.1 million. (Former "Tonight Show" host Conan O'Brien draws about 1 million nightly viewers for his show on TBS).

"I don't think anyone expects us to beat those guys coming out of the gate," Kimmel said of Leno and Letterman. "As it is now, we're kind of stuck in the middle of four different shows" because of the time slot.

Robert J. Thompson, who runs the Bleier Center for Television and Popular Culture at Syracuse University, sees Kimmel's time switch as era-defining.

"If he can compete in that period, I think that could completely change and finally solidify the idea that while 'Tonight Show' has got this long legacy and people like Letterman and Conan so much revere it, the fact is the 'Tonight Show' might not any longer be the holy grail of television."

He added: "I'm not even sure it's the holy grail now, to be honest."

Certainly, "Tonight" isn't throwing off the cash it used to. But gold mines have grown scarce in late-night TV overall, as competition and lowered ratings take their toll.

"Tonight" delivered a reported $100 million to NBC's bottom line during the show's 1990s heyday, but TV veterans say the show is barely profitable now. And most competitors are in similar straits.

Last summer, NBC forced layoffs at "Tonight" for only the second time in the show's nearly 60-year history. NBC executives declined to comment on reports that they are looking to jettison Leno as early as 2014 and replace him with Jimmy Fallon, currently the host of the network's 12:35 a.m. show.

Despite the recent history, ABC brass is optimistic about Kimmel's prospects.

"We think it's time," said Paul Lee, president of ABC Entertainment Group, in an interview. "We think we can build ourselves a big entertainment asset in late night."

That's not the plan Kimmel has for the rest of his career. "I'm not going to be one of those guys that they have to drag off the stage," he told reporters. "I mean, I look at it now and I think, 'You know, if we were lucky enough to be able to do another 10 years, I would be very happy with that.'"

Staff writer Meredith Blake contributed to this report.