"Jimmy Cagney was sick of making gangster pictures. The electrifying actor that had burned a path through such bullet-riddled classics as The Public Enemy (1931), Angels With Dirty Faces (1938), and The Roaring Twenties (1939) openly admitted that he disliked the roles that had garnered him so much fame and acclaim. He much preferred to try a large range of roles, including those in comedies and musicals. So, after his contract was up at Warner Bros., following his Oscar-winning performance in Yankee Doodle Dandy (1942), he decided to opt out of a new contract in favor of creating his own production company with his brother, William Cagney, where he could make his own decisions about roles and the types of films that he brought to the silver screen.
This new company produced only three films before it hit financial hard times. Johnny Come Lately (1943) is the story of a down-on-his-luck reporter that finds redemption at the boarding house of a small-town publisher and repays her by leading a campaign against a conniving politician. Blood on the Sun (1945) is another reporter-based drama, this one about an American in Tokyo caught up in international intrigue. The Time of Your Life (1948) is based on the Pulitzer Prize-winning William Saroyan play of the same name. In it, Cagney plays a wealthy man taking an interest in the lives of some saloon denizens, and spends much of the film sitting down.
Facing financial dissolution, the Cagney brothers went back to the Warner Bros., who welcomed them with open arms, giving them a substantial contract that included project approval, re-write approval and a percentage of profits from re-release and re-sale of previous Cagney-WB films. The logical choice to re-launch Cagney's career at Warners was a gangster film, one directed by Raoul Walsh, the same director that guided Cagney in The Roaring Twenties and himself directed what was arguably the first gangster feature back in 1915, Regeneration.
Cagney’s desire, however, in order to make the role more appealing to him professionally, was to make this gangster different. With encouragement from Walsh, Cagney pushed the character to the brink, and finally over the edge, of sanity. It is unclear how different the character is from the script as written, but there are well-documented instances where Cagney’s performance changed the character. It was Cagney's idea to have his character, Cody Jarrett, sit in his mother's lap on a bed while she was comforting him, creating a tableau that has famously led to speculation on their relationship. And it was Cagney that had Jarrett point to Big Ed's body with pride after shooting him, an act that couldn't have been scripted. And it was Cagney that belted out Jarrett's primal scream in the prison dining hall, laying raw his soul, a private moment in a public space.
Cagney's return to the milieu that begat his big screen career signified a distinct evolution in the gangster cycle, shifting the focus away from social conditioning toward a darker exploration of the gangster as psychopath. This characterization has been present ever since, in films as varied as Baby Face Nelson (1957), Goodfellas (1990), Reservoir Dogs (1992), The Road to Perdition (2002) and Gangs of New York (2002)"