"I think they made a choice of, 'We're going to make Kato Garth from Wayne's World,'" Kaelin told ET on Wednesday, admitting that the show makes him appear to be a stoner. "Can I do anything about it? Absolutely not."
Kaelin also took issue with some of the dialogue in the series. Twitter users called particular attention to a line uttered by Billy Magnussen, who plays Kaelin, in a scene where police show up at his door in the middle of the night.
"I'm not an official person," Magnussen says as Kaelin.
"I would never say that," Kaelin argued.
Additionally, Kaelin said that the crux of his testimony wasn't included in the miniseries. In the premiere episode, Simpson (played by Cuba Gooding, Jr.) gets in a limo by himself on the night Nicole Brown Simpson and Ronald Goldman were killed, but Kaelin testified that he was also in the limo, up front with the driver.
"There was a bag I was going to reach for and say, 'I'll get this,' and O.J. said, 'No, don't touch it. I'll get it,'" Kaelin recalled. "Well, that bag is not found. It was a very big part of my testimony."
During an impromptu live-tweeting session on Tuesday, Kaelin reminded viewers that American Crime Story is #NotADocumentary, and he reiterated the point on the ET stage.
"It's embellished," Kaelin said. "I think Robert Evans, the producer, said, 'There's three sides to every story: your side, my side and the truth,' and I think they missed a lot of the truth."
According to Kaelin, neither the producers nor any of the actors contacted him prior to making the miniseries, which surprised him, but he was more disappointed when he heard that the Browns and Goldmans weren't contacted either.
"I thought it was tasteless of a network not to tell the families of the victims, which it's based on, that they were doing a miniseries."
Kaelin is giving weekly reviews of The People v. O.J. Simpson: American Crime Story for The New York Daily News, and hosts an online anti-sports show called Sports Haters.