|Plot details follow, read at your own risk.|
Connolly previously worked as a mechanic before enlisting in the United States Marine Corps. Connolly was a member of the Sixth Marines, having fought in the Okinawa campaign alongside Lieutenant Cole Phelps and Sergeant Jack Kelso as a rifleman. On their way home from the war, Connolly and his fellow Marines were shipped on board the SS Coolridge. They reflected on the unsatisfactory jobs they were returning home to, prompting Courtney Sheldon to coax them into stealing the ship's cargo of army surplus morphine to sell on the streets. With the exception of Kelso, they committed the theft, stealing half a million syrettes.
Events of L.A. Noire
However, there was a feud between the established crime boss Mickey Cohen and Sheldon. Cohen started selling the dangerous morphine to the addicted, gaining a considerable advantage on the city's drug trade. Sheldon, realizing this, pulled out of the deal with Cohen.
Sheldon and Kelso arranged a meeting, with Alvarro holding the meeting in enfilade. Cohen later retaliated by ordering the assassinations of the Marines involved in the morphine heist. Connolly, along with John Higgins, were ambushed outside of the Grauman's Theatre by Cohen's men. Higgins miraculously survived unharmed, but Connolly was wounded in the crossfire.
Connolly recovered and later agreed to attack the mansion of Leland Monroe at Jack Kelso's request. Kelso, Felix Alvarro, Higgins and Connolly met along the perimeter and formed their attack plan. Afterwards, they stormed the courtyard, killing a number of Monroe's guards, before reaching the house. Once there, Kelso ordered Connolly and the others to maintain the perimeter and guard the house. Kelso entered the mansion to personally deal with Monroe.