Former stage and movie actor who filmed numerous documentaries for the US State Department, the Army and private industry in the late 1940s and began making low-budget features in the early 50s. Arnold concocted some of that era's classic science fiction-horror films, notably the pioneering 3-D efforts "It Came from Outer Space" (1952) and "The Creature From the Black Lagoon" (1954) as well as "The Incredible Shrinking Man" (1957).

A prolific director, mostly for Universal, Arnold worked in many genres, turning out 3-D mystery thrillers ("The Glass Web" 1953), teen exploitation flicks ("High School Confidential" 1958), blaxploitation actioners ("Boss Nigger" 1975), the wry Peter Sellers satire "The Mouse That Roared" (1959), and Bob Hope comedies including "Bachelor in Paradise" (1961) and "A Global Affair" (1964). By the mid-60s, Arnold had turned his attention increasingly to TV, as a director on "Rawhide", "Perry Mason" "Buck Rogers in the 25th Century", "Wonder Woman" and "The Bionic Woman", and as producer-director of "Mr. Lucky" (1959-60) "Gilligan's Island" (1964-67) and "It Takes a Thief" (1968-70).