Kimmel, whose "Jimmy Kimmel Live!" is moving from its 12:05 a.m. time slot on ABC to 11:35 -- when it will be in head-to-head competition with Leno's "The Tonight Show" on NBC, David Letterman's "Late Show" on CBS, and Conan O'Brien's show on TBS -- told Rolling Stone Leno "hasn't been a good stand-up [comedian] in 20 years."
"As a comedian, you can't not have disdain for what he's done," he said. "He totally sold out. He was a master chef who opened a Burger King."
Kimmel conceded, though, his show wouldn't be on "if the late-night landscape wasn't crowded."
"I'd be sitting home watching it on television if it weren't," he said.
Robert J. Thompson, who runs the Bleier Center for Television and Popular Culture at Syracuse University, told the Los Angeles Times the Kimmel time slot move could indicate a new era in late-night television.
"If [Kimmel] can compete in that period, I think that could completely change and finally solidify the idea that while 'Tonight Show' has got this long legacy and people like Letterman and Conan [O'Brien] so much revere it, the fact is the 'Tonight Show' might not any longer be the Holy Grail of television.
"I'm not even sure it's the Holy Grail now, to be honest," he added.