He won the Pulitzer for investigative reporting in 1988 for a series of stories about corruption in the Chicago City Council and shared the prize in 1976 for special local reporting on a series of stories about unsafe medical practices in some Chicago hospitals. He was also a finalist for the prize in 1995 for stories about financial dealings of the Nation of Islam. Gaines has been teaching reporting courses since 1975, first at Columbia College in Chicago, then at University of North Dakota, and since 1999, at the University of Illinois, Urbana-Champaign. Gaines has also written an investigative biography of jazz composer and performer, Jelly Roll Morton.