She was famous for starring in the biggest flop in Broadway history up until that time. A lavish 1929 Broadway musical, "Fioretta," was built around her
astonishing beauty by her boyfriend, producer/director
Earl Carroll. Knapp was badly miscast (she couldn't sing) in the starring role. The production was panned by critics and Carroll's backer, Mrs. Anne Weightman Penfield, lost a whopping $350,000. After it failed at the box-office, a promoter had
her fired. Dorothy sued. Soon after the lawsuit was filed, she
announced to the press that she was entering a cloistered
convent.