RHHDAS has 1902-1903 George Ade for "main (or head) cheese." This is

from the Asbury Park Daily Press, 11 November 1899, "Billy's Opinion of the

Drama" by John Hazelden (who wrote various slang items using Billy), pg. 3,

col. 3:

The fellow that she wuz stuck on was the main cheese of the play. He was

"it"--the real hero.