Tony Zerilli, a reputed underboss of Detroit's biggest crime family, said Hoffa was buried in a field in a Motor City suburb about 20 miles from the restaurant where he was last seen, WNBC-TV, New York, reported Monday.
Zerilli, 85, told the New York television station he wanted to correct any misconceptions about his life and what happened to Hoffa.
Zerilli denied being in the mafia or having anything to do with the disappearance of union leader.
"What happened to Hoffa had nothing to do with me in any way, shape or form," Zerilli said.
Investigators accused Zerilli of involvement in Hoffa's disappearance while he was in prison.
"If that's not an alibi, I don't know what the hell an alibi is," he said.
Zerilli said Hoffa never got very far from the restaurant, buried in a shallow grave in a field in northern Oakland County, Mich.
The plan to move the body later never happened, Zerilli said.
"Once he was buried here he was buried and they let it go," Zerilli said.
Barely able to walk, Zerilli told WNBC he was "dead broke. ... My quality of life is zero."
Andy Arena, former head of the FBI for New York and Detroit, told WNBC-TV Zerilli had risen "at one point to the underboss, or second in command" in the Detroit Mafia.
Zerilli said he was opening up now because he wants closure for himself and the Hoffa family, WNBC said.
"I'd like to just prove to everybody that I'm not crazy," Zerilli said. "And it means a lot to me. What happened, happened while I was in jail. And I feel very, very bad about it and it should never have happened to Jim Hoffa. He didn't deserve what happened to him."
Zerilli also is working on a book and has a website, hoffafound.com.
Hoffa was last seen at the Machus Red Fox restaurant in Roseville, Mich., on July 30, 1975. Over the years, his body has been reported buried under Giants stadium in New Jersey, dumped in the Everglades and set in the concrete of Detroit highways.