Walter is a simple man that spent his whole life in New York State, specifically around the Boston area. Born in 1896, he barely knew his parents before they were murdered - he was dropped off at an orphanage, and spent the next 18 or so years growing up there. He met his wife, Lillian, a few years later while volunteering at a library. Four years after meeting her, Walter proposes and they move into a small apartment-home together.
Walter started his job as a hitman around the age of 24, not long after marrying Lillian. He worked his way up in the "ranks" for the next 10 years. He never truly knew that what he was doing was bad - he was always fed lies, being told he was like an undercover cop, quietly taking out the bad guys. It wasn't until one of his jobs caused the demise of his wife that he knew he couldn't have been the good guy. He has since quit, and spends his time contemplating his decisions alone in his empty home.