He died Wednesday at Henry Ford Hospital in Detroit, the team announced. He had a bone marrow malignancy associated with lung and liver disease.
Clark was the offensive line coach for the Miami Dolphins team that went 17-0 in 1972. He became the Lions' coach in 1978.
"Monte will always be remembered as a consummate football man," Lions President Tom Lewand said. "He knew football inside and out, and had a passion for it. He played the game at a high level and had success wherever he coached."
Under Clark, the Lions went 43-63-1 and made back-to-back postseason appearances for the first time since their three straight playoff runs from 1952-54. The Lions lost both games.
Seven players were named to 14 Pro Bowls during Clark's stay in Detroit, including lineman Al "Bubba" Baker, kicker Eddie Murray and running back Billy Sims.
Clark was born Jan. 24, 1937, in Fillmore.
He starred as an offensive lineman at USC before San Francisco drafted him in 1959. He spent three seasons with the 49ers and one with the Dallas Cowboys before playing for the Cleveland Browns from 1963-69.
Clark served as an assistant to Coach Don Shula in Miami from 1970-75 before becoming head coach in San Francisco in 1976, leading the 49ers to an 8-6 record.
Clark returned to Miami as director of pro personnel in 1990. He served as offensive line coach at Stanford in 1993-94 and was Miami's offensive line coach in 1995.
He spent the 1998 season as offensive line coach at UC Berkeley and joined the Lions that year for the first of 11 seasons as a consultant. After his coaching career, Clark was a football broadcaster in Detroit and color analyst for the University of Michigan.
He is survived by his wife of 52 years, Charlotte; three sons and eight grandchildren.