In the later years of his career, Chris Farley’s physical comedy became more and more a form of self-flagellation. Photograph by NBC via Getty

Chris Farley, who died in 1997, at the age of thirty-three, from an overdose of opiates and cocaine, was the greatest physical comedian of his generation, a manic cannonball who could appear surprisingly athletic one moment and perilously ungainly the next, as likely to pull off a nifty cartwheel as he was to obliterate a piece of furniture. He was always big—plainly and dangerously overweight, owing in part to his genes and in part to his massive appetites for food and alcohol—and his thick neck and huge gut, stacked atop a pair of comparatively dainty legs, were a central part of his appeal. He shouted big, sweated big, laughed big, and fell down big.

These gifts were perhaps most obviously on display in the famous "Saturday Night Live" Chippendales sketch, from October, 1990, during Farley's first season on the show. In it, he plays an aspiring dancer, squaring off against Patrick Swayze for the last spot in a male revue. Dancing to the Loverboy hit "Working for the Weekend," Farley tore off his shirt and matched Swayze move for move—flying pirouettes, proto-twerking—to the shrieking delight of the audience. The joke of the sketch, as it was, came in the final moments, when a panel of judges bluntly confirmed what was obvious from the start: they were picking Swayze's character because of his great body. Farley's character, meanwhile, had the "sexiest moves," but was judged too "fat and flabby" for Chippendales.

A new documentary, "I Am Chris Farley," which débuts Monday night on Spike TV, frames the sketch as an unqualified triumph, the moment when Farley became a national star. But in the book "The Chris Farley Show," a rich and illuminating oral history compiled, in 2008, by Tanner Colby and Farley's older brother, Tom, it is the source of controversy among those who were there. Jim Downey, who wrote the sketch, insisted that Farley's dancing ability elevated it, so that the audience was celebrating his audacious performance rather than merely mocking his appearance. People were laughing with Farley, not at him—that distinction being one of the essential tensions of Farley's career. Bob Odenkirk, though, who was a writer on the show, recalled the entire thing as "weak bullshit," and said that Farley "never should have done it." Chris Rock, a cast member at the time, viewed it as a dangerous turning point for Farley. "That was a weird moment in Chris's life," he said. "As funny as that sketch was, and as many accolades as he got for it, it's one of the things that killed him. It really is. Something happened right then."

It was probably all of those things. A subtler but still outrageous showcase for Farley's physical brilliance came three seasons later, when he appeared as a hapless motivational speaker named Matt Foley, hired by suburban parents to scare their marijuana-smoking teen-age children straight. This is Farley at full bore, his knowing Midwestern verbal dexterity paired perfectly with his outlandish physical gifts; Foley's repeated catchphrase, "living in a van down by the river," soon entered the cultural lexicon. The sketch was new to national viewers, but it was a holdover from Farley's days with the Second City improv group, in Chicago. It was written for Farley by Odenkirk, also then at Second City, and the documentary includes grainy video footage of Foley's first incarnation. The character was all there from the beginning: we see Farley onstage in his low crouch, like an offensive lineman, bellowing out his misguided attempts at motivation, as he moves his hands back and forth wildly to hoist up his sagging pants.

But before Matt Foley went on national television, the sketch was given a new twist, as the writer Robert Smigel explained in the oral history. Near the end of the sketch, as Farley reaches the pinnacle of his deranged spiel, he trips and flings himself face down on a coffee table. It is shocking and funny, earning what is certainly the biggest laugh from the studio audience, and forcing Farley's scene-mates to cover their faces to hide their own laughter. Smigel said that he regretted adding it. "It worked really well, but it inaugurated this trend of Chris being really clumsy and falling down a lot.... That sort of broad clumsiness was actually the opposite of what Chris's talents as a physical comedian were."

As the years went on, and the pratfalls mounted—writers had discovered the shortcut to a sure laugh—Farley's physical comedy became more and more a form of self-flagellation: when he'd play at being angry with himself for saying or doing something inappropriate, he would pull his hair and slap his face hard enough that it must have hurt; when he took one of his recurring falls onstage, he did it for real, without anything other than his own body to soften the blow. This kind of thing helped cement his legend as being willing to do nearly anything for the good of a joke, to get and give the biggest laugh possible. It was gutsy and funny, but also gruesome, and more so in hindsight. In 1997, two seasons after he'd been fired from the show, Farley was invited back to "S.N.L." to host. He was spiralling out of control by then: he lost his voice during the dress rehearsal and was breathless throughout the live broadcast, a loud and wheezing shadow of his former self.

Near the end of his life, Farley is said to have become cynical about the basis of his broad appeal, lamenting that "fatty fall down" was his only reliable crowd pleaser. During what would be his last appearance on "Late Show with David Letterman," in 1996, Farley, sweating, unkempt and barely able to catch his breath, shouted out, "They're applauding 'cause I'm fat!" But Farley didn't live long enough to free himself from the kind of comedy that made him famous. In the oral history, Sarah Silverman remembers Farley once asking the "S.N.L." writer Jim Downey, in a childish voice, "Hey, Jim? Do you think it would help the show if I got even fatter?"

This kind of heedlessness led people to compare Farley to another "Saturday Night Live" force of nature turned comedy martyr, John Belushi. In the documentary, Lorne Michaels says that Farley was "the child that Dan Aykroyd and John Belushi didn't have." Farley himself was said to have been drawn to the Belushi mythology, as well. In the oral history, the writer Tom Davis recounts a conversation that he had with Farley:

I said to him once, "Chris, you don't want to die like Belushi, do you?"

And he said, "Oh, yeah, that'd be really cool."

And I actually started crying. I wept for him.

Chevy Chase said that at one point near the end of Farley's life, he cornered him and "read him the riot act," saying, "Look, you're not John Belushi. And when you overdose or kill yourself, you will not have the same acclaim that John did. You don't have the record of accomplishment that he had." But the Belushi-Farley connection only became stronger after Farley's death. Both men died from an overdose of heroin and cocaine. Both were just thirty-three when they died.