Morse was born in Mansfield, Texas. She was hired by Jimmy Dorsey when she was 14 years old. In 1942, at the age of 17, she joined Freddie Slack’s band, with whom in the same year she recorded “Cow-Cow Boogie (Cuma-Ti-Yi-Yi-Ay)”, the first gold record released by Capitol Records. “Mr. Five by Five” was also recorded by Morse with Slack, and became a hit record in 1942 (Capitol 115). She also originated the wartime hit “Milkman, Keep Those Bottles Quiet”, which was later popularized by Nancy Walker in the 1944 film Broadway Rhythm.

In 1943, Morse began to record solo. She reached #1 in the R&B chart with “Shoo-Shoo Baby” in December for two weeks. In the same year she performed “Cow Cow Boogie” in the film Reveille with Beverly and co-starred in Universal’s South of Dixie and The Ghost Catchers with Olsen and Johnson and How Do You Dooo?, a vehicle for radio’s “Mad Russian”, Bert Gordon. She sang in a wide variety of styles, and she had hits on both the U.S. pop and rhythm and blues charts. However, she never received the popularity of a major star.

In 1946, “House of Blue Lights” by Freddie Slack and Morse, (written by Slack and Don Raye) saw them perform what was one of many of Raye’s songs picked up by black R&B artists. Her biggest solo success was “Blacksmith Blues” in 1952, which sold over one million copies, and was awarded a gold disc. The same year her version of “Down the Road a Piece” appeared on Capitol with Slack again on piano accompaniment. Morse also recorded a version of “Oakie Boogie” for Capitol which reached #23 in 1952. Her version was one of the first songs arranged by Nelson Riddle.

Morse ceased recording in 1957, but continued performing until the early 1990s, under the new management of Alan Eichler, performing at such clubs as Michael’s Pub in New York, Ye Little Club in Beverly Hills, the Hollywood Roosevelt Hotel’s Cinegrill and the Vine St. Bar and Grill. She appeared regularly at Disneyland for several years with the Ray McKinley Orchestra, and did a successful tour of Australia shortly before her final illness.

In 1999 Morse died of respiratory failure in Bullhead City, Arizona, at the age of 75.

Her music career was profiled in Nick Tosches’ 1984 book, The Unsung Heroes of Rock ‘N’ Roll: The Birth of Rock in the Wild Years Before Elvis. She has a star on the Hollywood Walk of Fame at 1724 Vine Street. Her entire recorded body of work was issued in a deluxe box set by Bear Family Records and a rare live performance, “Ella Mae Morse On Broadway,” was released in 2011.