The cause of death has not been disclosed, but his sister, Loretta Kelly, told the Michigan news site MLive that he had been hospitalized several times in the last year.
Burton played Tony “Duke” Evers in the franchise’s first six films. He retired from acting in 2007, the year after his final “Rocky” movie, “Rocky Balboa,” was released.
Carl Weathers, who played Apollo Creed, confirmed Burton’s death Thursday night on Twitter.
“Sad news. RIP Tony Burton. His intensity and talent helped make the Rocky movies successful,” he wrote.
MGM, the studio behind the “Rocky” films, also paid tribute to Burton, tweeting “Rest in Peace, Tony.”
Burton initially played Apollo’s trainer in the original 1976 movie and its 1979 sequel, then acted as Rocky’s corner man after Apollo’s death in 1982’s “Rocky III.”
Burton also appeared in the films “The Shining,” “Stir Crazy,” “The Toy” and “Assault on Precinct 13,” as well as the TV series “The A-Team,” “NYPD Blue,” “Kojak” and “Twin Peaks.”
Before becoming an actor in 1974, the Flint, Mich., native was a professional boxer who won Michigan Golden Gloves light heavyweight titles in 1955 and 1957.