I doubt most knew about Marinaro as a footballer if talking Joe Public.
Same can be said about Fred "The Hammer" Williamson, and Carl Weathers and Bernie Casey.
Don't think any of the bodybuilder actors were forgotten as bodybuilders since they all played musclemen roles. Arnold so big in that sport he never escaped it, even as an old timer now. Same with Jim Brown.
There are a slew of old pro rasslers like Mike Mazurki, where it's.......he was a rassler?
Oh no, I realize he was a prolific mat performer, but have only seen footage of him in action as a referee. An earlier rassler we could mention might be Tor Johnson (depicted by George "The Animal" Steele in Ed Wood).
Among boxers who became far more famous as actors, Victor McLaglen successfully transitioned from top billing as a leading man in silents to talkies, won the 1935 Academy Award for Best Actor in "The Informer," appeared as himself in a 1937 cameo for Eddie Cantor's "Ali Baba Goes to Town," and was nominated as Best Supporting Actor for The Quiet Man. He really became a star with "What Price Glory?" in 1926. McLaglen was really what Max Baer, Sr. aspired to in Hollywood, but that was an impossible act to follow. He was still acting when he died of a heart attack at 72 in 1959 and received one of the inaugural stars on the Hollywood Walk of Fame in February 1960.