Upshaw's death was announced by the NFL Players Association, which he headed for a quarter century.
His outstanding 15-season playing career was entirely with the Oakland Raiders and included two Super Bowl wins and seven Pro Bowl appearances.
In 1983, he became executive director of the players' association and guided it through the 1987 strike that led to replacement football. By 1989, the players had a limited form of freedom, called Plan B, and in 1993, free agency and a salary cap were instituted.
Since then, the players have prospered so much that NFL owners recently opted out of the latest labor contract, which was negotiated two years ago by Upshaw and then-commissioner Paul Tagliabue.