Guy Gardner is a character, a comic book superhero published by DC Comics. He is a core member of the Green Lantern family of characters, and for a time (late 1980s through mid 1990s) was also a significant member of the Justice League family of characters.
He was created by John Broome and Gil Kane (who patterned him after actor Martin Milner) in Green Lantern #59 (March 1968), although the character was changed significantly in the 1980s by Steve Englehart and Joe Staton who turned him into a jingoistic parody of an ultra-macho "red-blooded American male." This latter remains the character's archetype to this date.
Source: CC Wikipedia