Most of his early film parts were uncredited bits, including ''
All the King's Men (1949) and Francis the Talking Mule'' (1950). Holdren soon won lead roles in the war comedy
Purple Heart Diary (1951) co-starring
Frances Langford, as well as
Captain Video: Master of the Stratosphere (1951) the serial version of the adventures of
Captain Video, becoming the third actor (after
Richard Coogan and
Al Hodge) to assume the role of the heroic Captain. Holdren portrayed
Aramis in the
Three Musketeers adventure film
Lady in the Iron Mask (1952) starring
Louis Hayward as
D'Artagnan and
Patricia Medina in the titular role. After
The Lost Planet (1953), Holdren tried to maintain a foothold in feature films and TV, but with limited success. He appeared in a number of ongoing TV series, such as
Dragnet and
The Lone Ranger, but usually in bit parts, often uncredited. His last significant film appearances were in very minor roles in feature films like
Jeanne Eagels (1957),
Ice Palace (1960), and
The Rise and Fall of Legs Diamond (1960). The rapidity of his descent is indicated by the fact that in
Commando Cody: Sky Marshal of the Universe (1953) he plays the lead role and Richard Crane plays his (semi-comical) sidekick, whereas in the TV series
Rocky Jones Space Ranger (1953–54) Richard Crane plays the lead role and Holdren has a walk-on part in two episodes as "Ranger Higgins". After 1960, Holdren became a full-time insurance salesman. During his Hollywood years, he was seen in public as the escort of many different Hollywood beauties, but he never married. == Death ==