Cole Porter picked James Stewart for the male lead and later said he sang "Easy to Love" as well as any professional singer. A dubbing track was prepared with baritone Jack Owens, but it was decided that Stewart's tenor voice was perfect for the song. In That's Entertainment! (1974), Stewart said, "The song had become a huge hit, even my singing wouldn't hurt it."
The cop in Central Park (played by Reginald Gardiner) spoofs conductor Leopold Stokowski and incorporates his long hair and dramatic gestures.
The submarine shown entering New York harbor toward the beginning of the film is in fact, the U.S.S. Pike. However, the P2 designation on the conning tower indicated that this was shot between December 1935 (when she was commissioned) and September 1938. The P2 is a class identifier and order number. In September of 1938 that would be replaced with Navy hull #173. She took part in World War II. Including directing bombers to Wake Island, where she was severely damaged by depth charges. She only sank one ship and damaged three others. At the time she was engaged the Navy was plagued with faulty torpedoes. By the middle of 1943 she was withdrawn and replaced by more advanced boats. She served out the rest of the war as a training boat. She was mothballed in 1945 and sold for scrap in 1957.
Geraldine Robertson played Chorine (uncredited). She landed the part as a result of being crowned Queen of the Centennial at the Texas State Fair in 1936, crowned by Ginger Rogers, and part of the prize for winning was a screen test with MGM.