Her father was Irish Philadelphian newspaperman, Benny McNulty. He was related to
Jim Farley, Roosevelt's campaign manager and later U.S. Postmaster General. As a child, she sang songs at a silent movie theater. After the sixth grade she joined a touring vaudeville act called "The Kiddie Kabaret." Billed as Penny McNulty, she sang and danced with
Milton Berle and
Gene Raymond. Her first speaking part was in a
Jack Benny Broadway show, "Great Temptations".
Moving to Hollywood, she took a new name after marrying dentist Lawrence Singleton. Her first name derived from having saved large
amounts of penny coins. She played a tough nightclub dancer in
After the Thin Man (1936)
and acted/sang/danced in
Swing Your Lady (1938), one of the movies Humphrey Bogart
regarded as his worst. Though naturally a brunette, she bleached her hair blonde ever since she got the role of Blondie in that long-lived series.