Los Angeles County coroner's spokesman Ed Winter said Smith was found dead at his Baldwin Hills home. Winter said he didn't know the circumstances or cause of death.
Police spokesman Richard French added the death does not appear to be suspicious.
The top overall pick in the 1967 draft after a sensational career at Michigan State, Smith spent five seasons with the Baltimore Colts and two seasons each with Oakland and Houston. He won the 1971 Super Bowl with the Colts.
One of the most feared defensive ends in the game, Smith often drew two blockers, yet was effective enough to make two Pro Bowls and one All-Pro team. His best work actually came in college, and Smith was enshrined in the College Football Hall of Fame in 1988.
Smith played for his father, Willie Ray Smith, in Beaumont, Texas, before heading to Michigan State, where he was an All-American in 1966.
As an actor his most memorable role was playing Moses Hightower, the soft-spoken officer in the "Police Academy" series. He also appeared in such television series as "Good Times," "Charlie's Angels," and "Half Nelson," and was a regular in the ground-breaking Miller Lite commercials featuring retired players.