Once dubbed the "baby mogul" after his remarkably quick ascent to producing success and executive status, Mount became, before reaching age 30, a force to be reckoned with at MCA/Universal and in the industry as a whole. After brief stints working for Roger Corman (whose "Frankenstein Unbound" he would produce in 1990), Danny Selznick and Ned Tanen of MCA/Universal, Mount was given responsibility for producing low-budget films for MCA in the late 1970s. Although he soon moved on to larger efforts, he would continue his line of modestly made, popular films as well during his seven-year reign at Universal from 1976 till the end of 1983.
During this time Mount was responsible for developing and overseeing the production of over 140 feature films, largely frivolous comedies, action films and routine horror fare, leavened with a reasonable smattering of adult drama, including "Car Wash" (1976), "Smokey and the Bandit" (1977), "National Lampoon's Animal House" (1978), "Coal Miner's Daughter" (1980), "Missing" (1982) and "Psycho II" (1983). For five of the seven years that Mount headed MCA, the studio tallied record earnings. He became especially noted for giving chances to a considerable number of untested directors, budding writers and fledgling stars and achieved perhaps his greatest satisfaction when appointed to the position his former boss Tanen had held less than a decade earlier. Mount also headed MCA's short-lived theatrical division which helped produce such Broadway shows as "The Best Little Whorehouse in Texas" (1979) and "Nuts" (1980).
On his own since the end of 1983, the cool and canny producer founded his own company and developed such feature films as "Can't Buy Me Love" (1987), "Tequila Sunrise" (1988), "Bull Durham" (1989), "The Indian Runner" (1991) and Sidney Lumet's "Night Falls on Manhattan" (1996). Mount also developed an amicable working relationship with Roman Polanski and helmed production chores on three of the director's films, "Pirates" (1986), "Frantic" (1988) and "Death and the Maiden" (1994).