Before Knapp went to Hollywood she acted on stage, including performing in road companies of
Billie Moore,
Broadway,
Mrs. Money Penny, and
The Patsy, She started acting in silent films, her first role being in the 1929 film ''At the Dentist's
. She was cast as leading lady in Smart Money'' in 1931, the only film starring both
Edward G. Robinson and
James Cagney. In 1932, Knapp was one of 14 girls, along with
Ginger Rogers and
Gloria Stuart, selected as
WAMPAS Baby Stars. In 1931, Knapp spent several months in a hospital after she fell from a cliff during a hike with her brother, Orville. Two vertebrae were fractured. Although she was ready to resume her career four months after the fall, she encountered doubts from film executives. In 1935 she said, "But it is only recently that I can walk into a producer's office without getting that solicitious, questioning look that says, 'I think you could do the part all right, but — do you really think you're strong enough?'" She achieved success in
cliffhanger serials, which were popular at the time. She played the title character in the 1933 serial
The Perils of Pauline. The same year, she starred, with top billing, alongside 26-year-old
John Wayne in
His Private Secretary, a light comedy in which Wayne portrays a playboy determined to win her over. She also appeared in
Corruption that year opposite
Preston Foster. One of her better known film roles was opposite
Ken Maynard in the 1934 film
In Old Santa Fe featuring
Gene Autry in his first screen appearance, in which he sang with a bluegrass band. She worked through 1941, but her career slowed afterward. In 1943, she played her last role, uncredited, in
Two Weeks to Live, one of the
Lum and Abner films starring
Chester Lauck and
Norris Goff. ==Personal life==