Louie Russo and his brother, Willy, were 'made' under Al Capone. His brother was one of the men sent to kill Vito Corleone during the Castellamarese war (mentioned in The Godfather), although he was eventually killed by Luca Brasi.
Russo holds a grudge against the Corleones for years for his brother's death, at one point attempting (unsuccessfully) to have Vito's son Fredo killed. After Michael Corleone becomes Don in 1955, however, Russo tricks him into believing that the bad blood between them is over. Under Russo, the Chicago mob expands into the New York area and interferes with the Corleones' Las Vegas casinos. Russo unsuccessfully conspires with Vincent Forlenza and Nick Geraci to kill Michael Corleone, in the process indirectly duping Fredo into betraying his brother to Hyman Roth.
In June 1961, he invites Tom Hagen to his supper club/gambling house in rural Illinois with the intention of killing him. He, Hagen, a rower, and two Russo soldatos go out on a gondola in his man-made lake. On the course of the trip, as part of Michael's revenge, Hagen strangles one soldato while the rower hits Russo and the other soldato with his oar. Hagen then personally kills Russo on his boat, with Russo's own gun, and dumps the bodies in the lake.
In his appearances in The Godfather Returns, Russo is portrayed as a cruel, vindictive man whose methods of retribution are particularly vicious, even by Mafia standards; in the sequel The Godfather's Revenge, Tom Hagen describes Russo as "a sick man, in ways I don't like to think about." Following an assassination attempt years before, in which his eyes are permanently damaged, he wears large black sunglasses to shield them from the light. When he inadvertently shows his uncovered eyes to Tom Hagen after his glasses are knocked off, Hagen notes that they are red with a green ring in the middle. The novel reveals that Russo is estranged from his gay son, but still uses him as a source of information on closeted rivals for purposes of blackmail and gamesmanship with other families.