Prior to joining the Globe in 2015, he worked at the Denver Post (CO) for 17 years as well as the Berkshire Eagle (MA) and The Marlboro Enterprise (MA.) In 2010, Walker won his first Pulitzer Prize for Feature Photography “for his intimate portrait of a teenager who joins the Army at the height of insurgent violence in Iraq.” In 2012, he won again “for his compassionate chronicle of an honorably discharged veteran, home from Iraq and struggling with a severe case of post-traumatic stress.”