Everyone loves a good hard-luck story. Jon Stewart, it shouldn't surprise you, is no exception. He's telling one about his first day on the job at the Quaker Bridge Mall outside Trenton. All he was doing was trying to make his co-workers laugh when he dove head first into a bean bag chair. Somehow, young Jon misjudged the plunge and went crashing into a wall of aquariums.

Hundreds of dead fish and $10,000 worth of aquarium equipment later, Stewart was fired by, of all people, his own brother. "He caught me trying to dump the fish into the incinerator," recalls Stewart. "He axed me on the spot. Thankfully, the Quaker Bridge Mall is like O'Hare Airport [in Chicago]. There's a hub and many, many terminals. You can be fired from every wing of the mall, and still keep going."

Looking boyishly handsome as he sips coffee in his Beverly Hills hotel suite, Stewart, 36, revels in telling stories that cast him as one of life's underdogs. He has a handful of job-from-hell anecdotes at the ready, including one that involves him being fired from a bakery for getting soap mixed up with flour.

So self-deprecating is this guy that he'd even rather talk about The First Wives Club, a movie he was cut out of, than the film career that Hollywood seems to have in store for him.

"Even when I saw a screening of First Wives Club,'I went, `You should take that guy out of there! Oops, that guy is me.'" he deadpans. "The truth of the matter is that all you can do is show up on the set, be as funny as you can be, trust the people around you, and hope it works out. And then you go home and write your own stuff."

Up until now, Stewart hasn't exactly been a slacker. In fact, he was once dubbed "the celebrity equivalent of lint" for his ability to pop up all over the place.

At the moment, he's is the host of the popular Comedy Central program The Daily Show. He's starring as Adam Sandler's best bud in Big Daddy, which opens Friday in area theaters. He's the author of Naked Pictures of Famous People, a book full of humorous musings. Before that, there was his TV talk show on Fox, which allowed him to realize his dream of sitting on William Shatner's lap. There was Stewart's many guest appearances on HBO's The Larry Sanders Show. And in September, there's a possible concert tour.

The last thing on Stewart's mind, it turns out, is movies.

"Look, I do a movie about once every 35 years," says the comic, who resides in Manhattan's West Village. "I've had a lot of them come out the last couple of months but I did those in bulk. It's like shopping for 800 pounds of grain and then never going back to the store again."

To date, Stewart has a few secondary movie roles to his credit, including turns as a teacher in The Faculty and as Gillian Anderson's main squeeze in Playing By Heart. But this week, Stewart hits the mainstream with Big Daddy, which was written and directed by the same team responsible for previous Sandler hits such as Happy Gilmore, Billy Madison, and The Waterboy.

In the comedy, Stewart plays a businessman who doesn't have a clue he fathered a child five years earlier. When he's out of town, the youngster shows up on his doorstep and Sandler has to take care of him until Stewart returns, which is not as easy at it sounds.

Stewart and Sandler go back a long way. They both started out at the same time, honing their stand-up acts in New York comedy clubs. "I always used to try to borrow money from Adam when he was making $15 a night," recalls Stewart. "He was a soft touch. Of course, now we have very little contact. Have you ever tried to have a conversation with someone who's being carried on a litter?"

It was, in fact, Sandler who suggested Stewart for the role in Big Daddy, which also stars Joey Lauren Adams (Chasing Amy), Leslie Mann (The Cable Guy), Rob Schneider (Saturday Night Live), and Cole and Dylan Sprouse (as the youngster).

"In many ways, Jon has the trickiest part in the movie," says director Dennis Dugan. "He's in the first 12 minutes of the film and in that short amount of time, he has to make enough of an impression on the audience so that when he returns at the end, they'll go, `I'm so happy that this guy came back!' And Jon achieved that. What he did with the role was remarkable."

Dugan might believe Stewart belongs in movies, but the comedian prefers his hosting duties on The Daily Show. Since taking over for the CBS-bound emcee Craig Kilborn in January, Stewart has received almost unanimous praise for his revamping of the satirical program.

"I'll be fired from this job eventually," laments Stewart. "People seem to have a four-month tolerance of me. Actually, I started out on Comedy Central with Short Attention Span Theater so when I went back, it was as if I was going home. I had a warm, cuddly Hope Floats kind of feeling."

On the show, Stewart had a field day commenting on the Monica Lewinsky-Bill Clinton mess. But when the crisis in Kosovo replaced Monicagate as the top news story of the day, the comic nearly hung up his quips.

"All of the images coming out of Kosovo were so horrific, you think, `This is tragedy. There's nothing funny about this.' And then somebody came running in the room and went, `Fabio got hit in the face with a goose!' That saved us for weeks. It was like receiving a gift from the gods."

The comic has always been blessed with wicked sense of humor. Back at Lawrenceville High School, Jon Stewart Leibowitz was voted the funniest member of his senior class.

After graduating from William and Mary College with a degree in psychology, Stewart decided to try and make a living out of being a smart aleck. His first gig was at the storied Bitter End on Bleecker Street. "You get the whole history of, `Woody Allen started here' and `Bill Cosby started here.' Let me tell you, they were long gone by 1987."

A half-dozen or so years later, with a successful career as a stand-up under his belt, Stewart started popping up as a talk-show host all over the cable TV dial. "I'm just lucky Pat Sajak went back to Wheel of Fortune when he did," cracks Stewart. "That means more work for me."

In fact, Stewart has all the work he can handle. Lately, he's been turning down movie roles to accommodate his Daily Show hosting duties. He's so settled in New York, he's thinking of starting a family with Tracey, his veterinary-student girlfriend of four years.

"Now that I've done Big Daddy, getting married and having kids doesn't seem so alien to me," he said. "Of course, I could always do the Anthony Quinn thing. When I turn 80, I could go, `I am full of life and sperm! Let's dance the dance of love.'

"Seriously. I'm the kind of guy who wants to be in the delivery room. I have experience in that area. The birth process is a lot like show business. You come out all happy and then some guy slaps you across the face."