O’Brien Growing Into ‘Late Night’ : Television: The show has been renewed ‘well into 1995,’ boasts improved ratings and the host who took over Letterman’s spot a little over a year ago is settling in.

NEW YORK — Stretching out his long legs in his office after a taping of “Late Night,” Conan O’Brien doesn’t look insecure about the future.

“I’m still in my childhood phase,” he says jokingly. “You know how a child measures his life, saying proudly, ‘I’m 5 1/2 years old!’? Well, I’m 1 year and 3 months old with this show. I doubt if Johnny Carson measured his tenure that way. But when you consider the number of shows that have come and gone in the past year, I think it’s an achievement to be here, with a show that’s improving in its comedy and doing better in the ratings.”

Almost from the time that O’Brien, 31, a former comedy writer who was unknown as a performer, was chosen to succeed David Letterman as NBC’s 12:35 a.m. host, someone somewhere has been predicting that the show would soon be canceled. Most recently there have been rumors that the network was considering dropping “Late Night” and expanding Greg Kinnear’s “Later,” which now follows it at 1:35 a.m.

But this week NBC, which has been renewing O’Brien’s show in 13-week cycles, again extended the run. Although the network declined to be more specific than “well into 1995,” sources said that “Late Night” will be around at least until February.

“We see improvement in both the quality and the ratings for Conan’s show,” said Rick Ludwin, NBC’s late-night programming chief. “That’s why we’ve renewed the show.”

With a 1.9 average rating for the third quarter of this year (representing about 1.8 million households), “Late Night’s” ratings have improved 15% in the last year. It is also averaging a 1.9 rating so far this fall, compared to a 1.2 for its newest competition, the syndicated “Jon Stewart Show.” David Letterman’s ratings for the last year he was on “Late Night” averaged a 2.6, according to NBC.

Despite the improvement, some of NBC’s affiliated stations remain unhappy with O’Brien’s ratings, believing they could reap larger profits by offering syndicated programming in that time period. Several threatened to drop the network show earlier this year, but NBC has held the line, and only Houston has done so, replacing “Late Night” with the show business newsmagazine “Extra.”

“The whole late-night landscape has changed, putting new pressure on shows,” Ludwin acknowledged. “There are a number of affiliates--some of them the same affiliates who felt this way about David Letterman several years ago--who feel that Conan’s show is not performing to the ratings level they want. There’s no make-or-break number, but we need to see ratings improvement in a timely manner, and we’ll be taking a good look at the November sweeps to see how the show is doing.”

Indeed--because more competition is around the corner. In December or January, CBS will launch a talk show with Tom Snyder to follow Letterman at 12:35 a.m.--although “we think he will attract an older audience,” Ludwin said.

“I think the important thing is that the show is going to be on the air at least for several more months,” said “Late Show” executive producer Lorne Michaels. “I think we’ll be around a year from now.”

For his part, O’Brien said that he is aware of the ratings. “But I believe the best thing I can do is to focus on the show itself,” he added. “We seem to be connecting with an audience who like what we’re doing and, hopefully, more people will hear about us and watch us as the show grows. If I went out there and tried to do a show that I thought would get a rating and didn’t try ideas--like having an ostrich deliver the lineup of our next night’s show--I’d think later, ‘If only we’d tried that ostrich bit--I would’ve been successful.’ ”

O’Brien, a former writer on “The Simpsons” and “Saturday Night Live,” Michaels and producer Jeff Ross have assembled a young writing staff, led by former “SNL” writer Robert Smigel, that has been winning praise recently from TV critics and others. O’Brien and Letterman have traded appearances on each other’s shows, and Letterman remarked on the air at one point, “The more I watch the show, I realize you guys do an incredible amount of comedy, and the stuff that is produced is very high level.”

In the last few weeks, the comedy segments have ranged from a Ken Burns-style historical documentary on O’Brien’s early years to “auditions” by computerized celebrities, from Michael Jackson to Jimmy Carter, to be jurors in the O.J. Simpson murder case.

O’Brien, who was nervous when he began interviewing guests a year ago, now comfortably trades jokes with a range of guests, from rock singer Cheryl Crowe to Sen. Bob Dole (R-Kan.). And sidekick Andy Richter, whose deadpan style was criticized when the show began, now has a cult following of fan-club members who come to the taping every Friday night. Many college students (whose TV viewing in dorms is not measured in the Nielsen ratings) write in that they are fans of the show.

“I don’t have a Plan B,” O’Brien said. “I’ve always wanted to be a talk-show host and, remarkably, I’ve been given that opportunity. At some point you have to just figure it’s ‘Field of Dreams’: If you build good comedy, they will come.”