In a scene in which June Allyson and Margaret O'Brien were supposed to cry to harmonica player Larry Adler's rendition of "Clair de Lune," the six year-old star asked director Henry Koster, "Shall I let the tears run all the way down my face, or shall I stop then halfway down?"
The member of the band at the Army base who breaks up Jimmy Durante's performance of "Umbriago" by singing in front of the microphone is Eddie Jackson (ne Edward Jacobs), Durante's long-time partner in the night-club team of Clayton, Jackson and Durante. The trio performed for years on vaudeville and at New York's Club Durant (sic) but it was the bottom-billed Jimmy who became the star. Lou Clayton, who gave up show business to manage his partner's career, made Jimmy a millionaire.
The director of the orchestra, José Iturbi, best known as an MGM personality, was the conductor of the Rochester Philharmonic Orchestra from 1936 to 1944.
During the Second World War when Music for Millions (1944) was made on the MGM lot in 1944, other than harpists there were very few women in major world symphony orchestras. In order to justify the cast of women instrumentalists who are June Allyson's roommates in the story, the on-screen orchestra has an unusual proportion of females, among them the dumb blonde Marie Wilson (My Friend Irma (1949)) on classical clarinet! Even today when there are numerous women in all major orchestras, it is still unusual to see as many women in the brass section as those who are pictured in this film.
Music for Millions (1944) was originally slated to be Lana Turner's first role after her pregnancy, but it was ultimately played by June Allyson.