[5] Discreetly gay during his acting career, he and his life partner Mark Miller were among Rock Hudson's closest friends.

[12] He had small parts in You're in the Navy Now (1951), The Prowler (1951), Take Care of My Little Girl (1951), The Desert Fox: The Story of Rommel (1951), and Two Tickets to Broadway (1951).

He made a number of films for Universal Studios, alongside leading men such as Rock Hudson, Tony Curtis, and Jeff Chandler.

[citation needed] His first film for Universal was a Western, Four Guns to the Border (1954), wherein he was billed beneath Rory Calhoun and Colleen Miller.

[6] He starred opposite Virginia Mayo in Congo Crossing (1956) and was second-billed to Chandler in Universal's expensive war epic Away All Boats (1956).

Nader moved into regular television roles in the late 1950s, appearing in several short-lived series, including The Further Adventures of Ellery Queen (1959) and The Man and the Challenge (1959–60).

He appeared in two Harry Alan Towers productions, The Million Eyes of Sumuru (1967) shot in Hong Kong and The House of 1,000 Dolls (1967) filmed in Spain.

In the 1970s, Nader suffered an eye injury in an automobile accident, which made him particularly sensitive to the bright lights of movie sets and forced him to retire from acting.

[6] He began writing, including his 1978 science fiction novel Chrome, which dealt with a forbidden romance between a man and an android (also male).

[21] Although Nader was not openly gay during his film career, he generally did not feign relationships with women to conceal it, instead deflecting questions by saying that he had not met "the right one".

He was survived by Miller (with whom he had spent 55 years), his cousins Sally Kubly and Roberta Cavell, and his nephew, actor Michael Nader.

[21] His ashes were scattered at sea; a cenotaph in his honor, together with Mark Miller and Rock Hudson, exists in Cathedral City's Forest Lawn Cemetery.