Married eight times? First to Ava Gardner? That's legend material right there. Plus 340 acting credits in the IMDB.
Seeing his juvenile roles I'm struck by what a wild boy he would play. When they said "hey kids, let's put on a show!" he'd be the out of control drummer in the band.
I hadn't thought of him for years when he showed up in The Black Stallion (1979), but it looks like he never stopped working, before or after. At whatever he could get, looks like.