The height-challenged comedian replaces Craig Kilborn on the irreverent half-hour on Monday.

Taking over The Daily Show on Comedy Central has Jon Stewart feeling small. Yes, that's a height joke - Stewart has a minor fixation on the fact that he's almost a foot shorter than lanky Craig Kilborn, whom he replaces Monday as host of the ultra-hip half-hour that skewers events of the day. In Kilborn's chair, "You wouldn't be able to see my head above the desk," Stewart says. But not to worry: NASA engineers have installed a booster seat. And tailors are working round the clock to alter Kilborn's suits to fit him. ("What'd you think, they'd just throw them out? Come on, this is basic cable.")

Kilborn, the original host of The Daily Show, quit after 2 1/2 years to take over for Tom Snyder late nights on CBS. (His run starts March 30.) How'd Stewart get the replacement gig? "I was the eighth caller." (Alternatively, he's suggested that he flew bombing sorties over the network until he was hired.) The truth is that Stewart, 36, was a real catch for Comedy Central.

Increasingly in demand as an actor, he'd had offers for a sitcom pilot and had talked to David Letterman's Worldwide Pants about doing a talk show. Industry rumors at various times had him taking over for Snyder and, bizarrely, replacing Garry Shandling in a revamped version of HBO's Larry Sanders Show.

But Stewart was drawn to Comedy Central by old friends. He knew Madeleine Smithberg, executive producer of The Daily Show and Eileen Katz, now a top-level programmer at Comedy Central, from MTV, which recruited him from stand-up comedy to launch The Jon Stewart Show in 1993.

The half-hour talker generated so much buzz that Paramount plucked it for syndication, expanding it to an hour and relaunching it nationwide in the fall of 1994 to replace The Arsenio Hall Show. Ratings were lousy, and just 10 months later, The Jon Stewart Show was canceled.

Stewart, whose style is wryly low-key, was philosophical about the failure. "Yeah, I miss the TV show, but... it's not like I eat a cheeseburger and say, hey, this cheeseburger is good, but not as good as my talk show," he told a Post-Dispatch interviewer in the fall of '95, after he'd returned to the comedy circuit.

In retrospect, he's even more philosophical, crediting the demise of the talk show with giving him the freedom he needed at that point in his career. "I had so many ideas floating around that I had to get out of my system, to put at ease," he says. "Movies, a book...."

Stewart was trimmed from The First Wives Club, in which he played Goldie Hawn's boyfriend, but went on to do The Faculty, the teen horror flick now in theaters, and Playing by Heart, opening Jan. 22, in which he got to kiss Gillian Anderson of X-Files fame. He's also in the forthcoming Adam Sandler flick Big Daddy.

On Larry Sanders, which ended its run last spring, he played a parallel-universe version of himself. "At first, I was playing me, but not well. Then, in the last season, I got a full-blown story line and a chance to go outside myself. To make it work, I really had to stretch." The results were both hilarious and eerie. That final season, while the fictional Larry (Shandling) worried that the semi-fictional Stewart would take over his show, rumors grew that HBO might actually recruit Stewart to take over for Shandling so the show could go on. But the rumors were completely unfounded, Stewart says.

"This was a gold-standard show. There was no reason to stretch it out, and I'm glad it was allowed to go in a dignified way." Resurrecting it in the future might be a possibility, though, "when they're all in the old actors' home, especially if I need work."

Sanders was wrapping up at the same time Stewart was finishing his book, a collection of humorous essays that he titled Naked Pictures of Famous People in the hope that "Naked" would boost sales. (For whatever reason, they've been good.)

After a frantically busy few months, Stewart found himself with time on his hands, some of which he spent surfing TV and yelling back at the set. "I have no real interests or hobbies," he notes. "I'm the least active person you can imagine." His only real avocation, Stewart claims, is chain-smoking, but he is obsessed with -- and appalled at -- the news. "How can you go wrong doing a show of topical humor with what's going on in the world? Just look at the White House. Satirizing that is just irresistible."

Stewart will serve as co-executive producer of the newly titled Daily Show With Jon Stewart and do much more writing than Kilborn. "That's really my favorite thing," he says, "sitting in a room with funny people till somebody hits on just the right bit."

But except to tape promos, he didn't even start work at Comedy Central until last Monday ("That Daily in the title means there's not a lot you can do way in advance"), and remained unsure in the interim of how the new show would differ from the old one, which featured a mix of edgy commentary and "field reports" on bizarre topics, with a nightly celebrity guest.

This much is known: Stewart's Daily Show will retain correspondents Beth Littleford and Stephen Colbert; A. Whitney Brown and Brian Unger have departed, along with Kilborn's signature "5 Questions" segment, which he created. The bottom line, however, is that "the fuel for this show remains the news, and I love that. It's so much better than a talk show, where the fuel some nights can be the fourth lead from Melrose Place."

In the beginning, Stewart says, he just wants to avoid screwing things up for an established and popular show. "My first priority is going to be to fit in. I mean, they've got the rhythm section going, and I don't want to be the guy clapping out of time. Before I even think of putting my so-called stamp on anything, we need to get the show running as smoothly as it was before Craig left. You have to drive the thing before you can fly it." All those involved agree on "the basic integrity of the show," Stewart says. Pause. "It is the one with the cartoon kids, isn't it?"