James Conway "Jimmy" O'Donnell is the anti-villain-turned-secondary antagonist of the 1984 gangster film Once Upon a Time in America.
He was portrayed by Treat Williams, who also played Xander Drax in The Phantom.
Jimmy is initially a legitimate union boss who wants nothing to do with criminals and gangsters, but is persuaded into the lifestyle by Noodles, Max and the gang when they promise to provide muscle for him, help him financially and to protect him from rival mobsters attempting to assassinate him. Eventually, he succumbs to greed, power and corruption, and becomes the leader of the teamsters' union, and a major part of the American Crime Syndicate.
He, the Syndicate, and various corrupt cops helped Max fake his death, take the gang's money, and start a new life as Senator Bailey, where Max married Noodles' love interest Deborah along the way. However after a political scandal and Max having found out too much about their criminal activity.
Jimmy attended Max/Bailey's party to inform him that he and the Syndicate have marked him for death, promising to protect Max's family and son, if Max were to die, either by murder or suicide. Jimmy soon left the party after this, leaving Max to confront Noodles after 35 years.