The 49ers said Matthews died Thursday. He had been dealing with a long illness.
Matthews was a two-way player for San Francisco for four seasons in the 1950s. He played in 45 games and missed two seasons while serving in the Korean War.
His impact on the NFL is still felt today. His two oldest sons, Bruce and Clay Jr., each spent 19 seasons in the league. Bruce received seven first-team All-Pro selections and was elected to the Pro Football Hall of Fame. Clay Jr. was a four-time Pro Bowler for Cleveland.
Five of Matthews' grandsons have also played in the NFL, including Green Bay linebacker Clay Matthews III and Atlanta offensive lineman Jake Matthews.