"When the Moon Comes Over the Mountain" is a popular song, published in 1931, and credited as written by Howard Johnson, Harry M. Woods, and Kate Smith. As Johnson is primarily known as a lyricist and Woods, when collaborating with lyricists, primarily wrote music, the actual apportionment of the credits would be likely to be music by Woods, lyrics by Johnson, and possibly some small contribution by Smith in order to give her a share of royalty income.
"When the Moon Comes Over the Mountain" became Kate Smith's theme song on radio and television, including her last CBS series, The Kate Smith Show in 1960.
This song was hummed by Groucho Marx during the breakfast scene in "A Night at the Opera".
References
When the Moon Comes over the Mountain Wikipedia(Text) CC BY-SA