- "Who do you think you are? Do you know what I went through over there? Do you know the sacrifices I made for you? I come back after years of fighting for this country and this is my welcome home?"
- —James Zolomon to his wife, before assaulting her[src]
James fought in the War of the Americas for many years, wearing a silver kettle helmet. When he returned home, he found that his wife, Ashley, was attempting to leave him for unknown reasons. He became violent, and started assaulting her. Their son, Hunter, walked in on them and James, angry with his wife, gave Hunter his kettle helmet and forced him to watch as he murdered the boy's mother with a shotgun. Following the ordeal, James was convicted and sent to prison, while his son was sent to live at the Central City Orphanage.  These events would continue to haunt and traumatize Hunter for the rest of his life.
His son alluded to his father's death at some point of time, mentioning that he witnessed it, and wanting Barry to experience the same right before he killed Henry.
James is a mentally unstable person who served in the War of Americas. While believing he was a hero for serving in the war, in reality he was considered a "monster" by his wife. He is a ruthless and cruel individual who physically abused his wife Ashley, and ended up killing her in front of his son which lead to Hunter becoming as mentally unstable as his father. 
Murdering Ashley is what led to James' deserved/justified incarceration.
Behind the scenes
- In the DC comics, the name of Hunter Zolomon's father is unknown. His backstory is also significantly different; Hunter's father was not a war hero but a serial killer who had killed six young girls, and when his mother told the police, his father murdered her on the day Hunter was to leave for college. Hunter's father was subsequently killed by the police after refusing to give himself up.
- While James is the original owner of Jay's helmet in the Arrowverse, in the comics, it originally belonged to Jay's father, a World War I veteran.