The name Mylee is of American origin and means "Smiley." The origin is the culture in which the name originated, or in the case of a word--the language in which it most appears.
The name Miley grew in popularity after the success of teen actress and singer, Miley Cyrus. Although Miley's birth name was Destiny Hope, she was nicknamed "Smiley Miley" by her parents as a baby. Cyrus legally changed her name to Miley in 2008.