Details from http://en.wikipedia.org/wiki/Cobra_Commander
Cobra Commander is a fictional character from the G.I. Joe franchise. He appears in the toyline, animated series (the 1985 and 1989 incarnations, the Sigma 6 and newest Renegades series), comic books, video games, and movie as the usual principal antagonist. He is the supreme leader of the terrorist organization Cobra, and archnemesis of the Joes. The character was created by Marvel Comics writer Larry Hama.
Cobra Commander (who is named Rex Lewis) is portrayed by Joseph Gordon-Levitt in the 2009 live-action film, G.I. Joe: The Rise of Cobra.