Elmer Clinton "Gloomy Gus" Henderson (March 10, 1889 – December 16, 1965) was an American football coach.

Henderson arrived at the University of Southern California (USC) in 1919 and set the Trojans football team on its first steps toward national prominence.

[1] Gordon Campbell, a halfback USC's 1923 Rose Bowl team, said of Henderson, "He put the Trojans on the map.

"[2] Under Henderson's tenure, USC joined the Pacific Coast Conference in 1922 and, in 1923, moved from Bovard Field on campus to play in the Los Angeles Memorial Coliseum.

He received his nickname from Los Angeles Times sports editor Paul Lowry because of his tendency to poor-mouth the Trojans' prospects before a game.

Regarding his offensive tactics, which proved successful, Los Angeles Times sports editor Paul Zimmerman noted, "Until someone proves otherwise, it must be assumed that Henderson invented the spread formation, variations of which have become an important form of attack in modern day football.

Henderson left USC following the 1924 season, despite a 45–7 record, partly due to his inability to defeat rival California in five tries.

USC quarterback Chet Dolley was dismissive of the idea, noting, "That was really a joke, because the university didn't have a dime."

"[2] Among the other players who arrived at USC during Henderson's tenure was the school's first two All-Americans, Brice Taylor and Mort Kaer, as well as future Pro Football Hall of Famer, Red Badgro.

In 1939, Henderson was hired as coach of the National Football League's Detroit Lions by team owner Dick Richards, who also owned Los Angeles radio station KMPC.

Henderson replaced Earl "Dutch" Clark, who had resigned to take a job as head coach of the Cleveland Rams.