At the ending of Lazarus it is revealed that Jimmy is alive, and is with an unknown woman(Angela). Taking up the alias "Jack", he and his female accomplice pull up to the Gallagher house and she asks him if this is the house, and if he wants to go in. Jimmy says "No, not tonight."
Jimmy makes an appearance in Rite of Passage. After greeting her mysterious female customer, now known as Angela, "Hey, you came back after all!", Fiona is answered by Jimmy from across the restaurant booth, who states "I did."
During Tell Me You F**king Need Me, Fiona tells her husband, Gus, that she cheated on him and Gus wishes to meet Jimmy. Jimmy agrees and they meet at Patsy's Pies. Jimmy says hello to Gus then Gus punches him in the nose and walks off. Soon after, Jimmy comes and sits outside with Fiona where she explains she doesn't want to be with Jimmy because she needs something different and doesn't live for Jimmy's dangerous personality any more. Jimmy then follows the footsteps of Gus and walks off. Jimmy musters up courage and tells Fiona to have a good life, and she says the same. Jimmy drives off on his motorcycle and Fiona starts walking off. Angela shows up in her expensive car and says she likes Fiona and calls 'Jack' an asshole.