Tall with reddish-blond hair, Arndt was originally a commercial bush pilot in Alaska while studying at the University of Washington. Although he had had some acting aspirations earlier, he thought his military service as a helicopter pilot during the Vietnam War had "cured" him. Asked by a friend to audition for a community theater production, Arndt soon felt the lure of the stage and went on to work extensively at the Oregon Shakespeare Festival and Seattle Repertory Theatre. He was one of the co-founders of the Seattle-based experimental theater, Intiman. Arndt appeared at the New York Shakespeare Festival in the title role in "The Ballad of Soapy Smith", which he had originated in Seattle.
The actor broke into films as John Lithgow's buddy in "Distant Thunder" (1988) and he had one of his biggest screen roles (to date) as Michael Douglas' boss in the hit thriller "Basic Instinct" (1992). More recently, he was seen as Eddie Murphy's boss in "Metro" (1997) and the TV miniseries "Peter Benchley's 'The Beast'" (NBC, 1996) and "Asteroid" (NBC, 1997).