CBS's Uncle Buck, based on the John Candy film comedy about an obnoxious, food-scarfing but ultimately lovable freeloader, caused a media ruckus this fall with the very first line of its very first episode, when Buck's little niece yelled, "You suck!' " at her brother. Kevin Meaney, who plays the sitcom's title role, is familiar with the sentiment from his early years as a comic. There was, for instance, the misguided attempt at Don Ricklesian humor at a dinner club in Cleveland. "I got up there," says the 34-year-old comedian, "and started making fun of people. These people in the audience decided they weren't going to pay because I was making fun of them. I got kicked out, and the owner is running after me, going. 'You owe me money, you jerk!' "

Then there was the time the new cap on his front tooth came loose and fell to the stage. "A woman in the front is going, This is disgusting!' And I'm going, 'Where is my tooth?' I'm down on the floor because I just paid thousands of dollars out of my own pockets for this. The woman keeps saying, 'This is disgusting!" And I've got just this bloody post dangling there in my mouth." And what about the 1980 San Francisco comedy contest? He placed 39th out of 40 contestants—and one had dropped out.

Then there was a very strange episode—a 1986 tryout for Saturday Night Live—when it seemed that even his cooking wasn't good enough. "Instead of bringing the resume and pictures," he says, "I baked an apple pie and brought in plates, knives and forks. They go, 'It's very nice to meet you, Kevin.' I say. 'Well, I thought it'd be a good idea to serve you some home-baked pie.' I remember stopping by my parents' on the way, and I said, 'I've got this great idea." My parents were going, 'You're an idiot.' "

His parents were right about the pie. He wasn't hired. But it turned out that his parents were right, exactly right, in a different way—as material. After yet another unsuccessful gig, this one in San Francisco, Meaney went home and decided, "I really have to come up with something funny." For once, the muse of stand-up complied. "I wrote most of my act that night. I wrote down some things about my childhood" (he grew up in Valhalla. N.Y., the third of five kids in a middle-class Catholic family), "A lot of that became major chunks of what is still my act," including whiny renditions of his mothers rule against light clothing ("We're a big-pants family!") and her concern that he'd wreck the family car ("We'll lose the house!").

Mom was initially mortified. "I used to die when he did that stuff. I'm shy," says Patricia Meaney, 61, a retired librarian who runs an antique-clothing store in Tarrytown, N.Y. "I never said most of the things he says I did. But being as I had four boys, I did used to say something like, 'Watch yourself, or we'll lose the house' when they'd borrow the car." Dad John, 63, who runs an antiques shop next to his wife's, had his moment of horror earlier, when Kevin, age 6, was the only boy who volunteered to sing at a Cub Scout dinner. "He didn't want to gel off the stage," his dad says. "It seemed like he was up there for hours. He did one song, and that was great. But then he did another and another. I finally had to pull him off."

Little Kevin had shown some performing ability in pageants at the local Catholic school, but he says that he couldn't really cut loose in roles that required "walking around the church, blessing things," and that the nuns weren't the best audience for his endless jokes. He switched to public school in the fifth grade, "so I could have more freedom." After acting in high school and college, Meaney left the State University of New York in Morrisville in 1976, after less than two academic years, and began his woebegone professional ascent, finally achieving noteworthy success with a 1987 appearance on The Tonight Show. His lip-synched rendition of "We Are the World." performed while mimicking Bruce Springsteen, Michael Jackson and all 40-plus of the song's singers, won Meaney an invitation to the sanctum sanctorum of American TV comedy—Johnny's couch.

The next rung up—starring in a sitcom—hasn't come without sacrifice. When Meaney moved from a Manhattan apartment to his current home, a two-bedroom rental in the Toluca Lake neighborhood outside L.A., he also had to move on from a long-term girlfriend. "We broke up this past summer," says Meaney. "It was a messy breakup, and I feel bad that it ended the way it did, but I'm much happier that I made the decision."

Filling John Candy's shoes was less difficult. "Kevin is Candy-esque because he's big," says Uncle Buck's executive producer, Tim O'Donnell, "even though he's not nearly as big as Candy [Meaney, at 5'9", is a mere 190 lbs.]. But he has a big, goofy persona and a swagger about him." And it doesn't hurt that Meaney started off with Candy's blessing. "The first week of production he sent me a bottle of champagne and a card that said, 'Much success,' " says Meaney, who then turns pensive. "I haven't heard from Candy since," he muses. "Maybe I could send him an apple pie."

—Tom Gliatto, Craig Tomashoff in Los Angeles