A graduate of the American Academy of Dramatic Arts, blonde Evelyn Knapp made her Broadway debut in Channing Pollock's Mr. Moneypenny (1928). With a proven track record of more than 20 Vitaphone short subjects and a series of comedy two-reelers with George LeMaire, she was awarded a contract with Warner Bros. and made an auspicious screen debut opposite Grant Withers in Sinner's Holiday (1930). The secondary team of James Cagney and Joan Blondell ran away with most of the notices but at least one critic thought Knapp gave a "credible performance" as a naive girl caught between rum runners and a young carnival barker.
In typical Warner fashion, Knapp was hurried from one project to another with very little thought to the appropriateness of the vehicles. From a muscular Northwest adventure with Charles Bickford, River's End (1931), she was rushed into playing George Arliss' refined daughter in The Millionaire (1931) with barely a chance to shift gears. In all her films, Knapp was pleasant and unobtrusive and in 1932, motion picture advertisers voted her a WAMPAS Baby Star. Being inconspicuous, however, was not exactly a star-making trait and Warners dropped her option, despite a starring role opposite John Wayne in the 1933 . Freelancing, she reportedly beat 50 actresses for the title role in Universal's remake of The Perils of Pauline (1934) and although Knapp was hardly in a league with the original Pauline, silent serial queen Pearl White, the chapterplay has proven the production for which she is best remembered. It was downhill from there, alas, and Knapp spent her remaining years in films in low-budget fare.