Blond, slightly built Scottish juvenile lead of English stage and film in the 1950s and early 60s before moving to Hollywood. McCallum's dreamy eyes and serious, thoughtful demeanor lent credibility to his portrayals of scientists, educators and other brainy types but stardom came when he was cast as the introverted Russian-born superagent Illya Kuriakin in the campy espionage series "The Man From U.N.C.L.E." (NBC, 1964-68). Teamed with the flashier, urbane Napoleon Solo (Robert Vaughn), Mr. Kuriakin worked for United Network Command for Law Enforcement in their never-ending battle to save the world from the sinister crime syndicate THRUSH (Technological Hierarchy for the Removal of Undesirables and Subjugation of Humanity). Often clad in black slacks and black turtleneck sweater, McCallum became a teen idol as the increasingly silly show benefited from two crazes of the era, the James Bond films and the British Invasion in popular music. He was featured prominently in the eight theatrical features cobbled together from series episodes.

McCallum's new star status was shrewdly exploited by American International Pictures in their teen rock concert film "The Big T.N.T. Show" (1966) as he introduced such big acts as Ike and Tina Turner, Joan Baez and Ray Charles and even conducted the Ray Charles band. This was actually less wacky than it may now appear since McCallum was trained--albeit briefly--at the Royal Academy of Music in London. The son of the first violinist of the London Philharmonic, McCallum played the oboe as a child. He switched to acting in 1949, attended the Royal Academy of Dramatic Art and began his career performing in repertory theaters and directing plays for the Army. McCallum began appearing in British films in the mid-1950s and shifted to Hollywood with impressive supporting roles in two interesting 1962 films John Huston's "Freud" and Peter Ustinov's "Billy Budd". He garnered greater attention in "The Great Escape" (1963) as a self-sacrificing POW camp escapee and "The Greatest Story Ever Told" (1965) as a disconcertingly boyish and fresh-faced Judas Iscariot.

After his hit series finally cried "uncle", McCallum remained a familiar TV face in the US and Great Britain. He returned to the milieu of "The Great Escape" as part of the ensemble of "Colditz" (BBC, 1972-73), a critical and commercial hit in the UK set in a German POW camp during WWII. Back in the states, McCallum starred in an acclaimed "Hallmark Hall of Fame" special entitled "Teacher, Teacher" (NBC, 1969) as a tutor struggling to rebuild his teaching career after battling alcoholism. He returned to series TV with the short-lived sci-fi adventure series "The Invisible Man" (NBC, 1975-76). After that gig dematerialized, McCallum appeared in numerous TV-movies, miniseries and guest shots often playing military officers, English investigators, Russian spies (!) and scientists. After decades of infrequent work in obscure genre films, McCallum had a small but pivotal supporting role in the well-received Irish feature "Hear My Song" (1991) as the grimly determined English policeman nemesis of Ned Beatty.