Norma Deloris Egstrom, born in Jamestown, N.D., on May 26, 1920, had a reason to leave her given name behind. After her mother’s death, when Egstrom was 4 years old, her alcoholic father and cruel stepmother made life at home difficult. When a local radio host suggested she go by Peggy Lee instead, the girl formerly known as Norma began a new and sunnier chapter.
LIFE profiled Lee in 1948, when she was 27 and already half a decade into her career as a singer. After two years singing with Benny Goodman’s band and a string of hits in the early 1940s, Lee released the song “Mañana" in January of 1948; it had sold more than a million copies by the time LIFE's profile ran in March. She would go on to win three Grammys, an Oscar nomination and an induction into the Songwriters Hall of Fame, performing into the 1990s until failing health forced her to retire.
But the Lee who LIFE profiled was not just an incredibly successful singer. She was also a working mother: “Betweentimes Miss Lee sees as much as she possibly can of her 4-year-old daughter Nicki. When she cannot, Nicki plays herself to sleep with one of her mother’s records.”
Liz Ronk, who edited this gallery, is the Photo Editor for LIFE.com. Follow her on Twitter @lizabethronk.