The son of Thurgood Marshall, the first African American U.S. Supreme Court Justice, John W. Marshall began his career in public safety in 1980 as a Virginia State Trooper. During his time with the department he also served as a Special Agent in narcotics investigations, and spent his final 5 years as a member of the motorcycle squad.

In 1994, President Clinton appointed Marshall to be the U.S. Marshal for the Eastern District of Virginia. In 1999, he was appointed once again by President Clinton, this time to serve as the Director of the U.S. Marshals Service, a position he held until January, 2001.

In 2002, he was appointed Secretary of Public Safety for the Commonwealth of Virginia by Governor Mark Warner. In 2006, he was re-appointed to that position by Governor Tim Kaine and remained in office until January, 2010. Marshall returned to federal service in March, 2013, as the Director of the Office of Safety Programs with the National Highway Traffic Safety Administration.

Marshall earned his undergraduate degree from Georgetown University, with a major in Government.