Who is the song low by that Tom Cruise sings in tropic thunder?

The song "Low" that Tom Cruise's character, Les Grossman, sings in Tropic Thunder is not a real song. It was written specifically for the movie and is not performed by Tom Cruise.

The song is a parody of typical pop songs, and it's intended to be a comedic portrayal of a self-absorbed and delusional Hollywood executive.