Luke Halpin as Sandy; it later became a popular, beefcake heavy tv series.
In the Doris Day comedy Move Over, Darling (1963), Ellen (Doris) is lost at sea and presumed dead, so after five years her husband Nick (James Garner) moves on. But Ellen resurfaces during his honeymoon. Hijinks ensue. Chuck plays Steven Burkett, the handsome, athletic, leopard-skin swimsuit-clad man she shared a desert island with for five years. Nothing happened, however.
Some dramas and Westerns followed, including Synanon (1965), with Alex Cord; Branded (1966-67), about a man unjustly drummed out of the army for cowardice ("what do you do when you're branded, and you know you're a ma-aa-n?"; and Cowboy in Africa (1967-68), which I never saw, but appeared to be about a same-sex couple (Chuck Connors, Tom Nardini) who run a ranch in Kenya and adopt a native boy. It was based on the movie Africa: Texas Style, starring Hugh O'Brian.
I didn't seem much of Chuck during the 1970s; he appeared mostly in Westerns, which I didn't care for. But he appeared again in Werewolf (1987-88), which starred hunky Eric (John J. York), a college student bitten by a werewolf; Chuck played evil head werewolf Janos Skorzeny, the object of Eric's quest to free himself from his curse.
But here's a censored full-frontal. It looks a lot like him.