In the third novel, titled Judgment Day, this character has an affair with Catherine Banahan, despite loving Catherine Scanlan.  
Some of the characters in the first novel about this fictional person include Paulie Haggerty, Kenny Kilkenny, and Iris, a fourteen-year-old proponent of free love.  In the second novel, Davey Cohen remains a fixture, and Phil Rolfe dates this character's sister Loretta while Danny O'Neill provides the author's commentary on the events.  In the third novel, titled Judgment Day, this character has an affair with Catherine Banahan, despite loving Catherine Scanlan.  FTP, identify the hero of this trilogy by James Farrell.
Some of the characters in the first novel about this fictional person include Paulie Haggerty, Kenny Kilkenny, and Iris, a fourteen-year-old proponent of free love.  
Studs Lonigan