Joseph McCarthy and Harry Carroll wrote "I'm Always Chasing Rainbows" in 1918 for the musical comedy "Oh, Look!" Carroll's melody is based on Chopin.

 

"I'm Always Chasing Rainbows" by Harry Nilsson

 

"Oh, Look!" starred Harry Fox and the Dolly Sisters. The Dolly Sisters were Roszika Dolly and Jansci Dolly.

 

"I'm Always Chasing Rainbows" was in the 1945 film biography The Dolly Sisters starring Betty Grable and produced by George Jessel. The film focuses on the romance between Harry Fox and Jansci Dolly ("Jenny").

 

The song was also in MGM's Ziegfeld Girl in 1946 and the 1973 Broadway musical "Irene" starring Debbie Reynolds.

 

The song has been recorded by Harry James, Perry Como, Helen Forrest, Harry Nilsson, and Dick Haymes.