From 1965–1966 Caputo served in the Republic of Vietnam (RVN) as an infantry lieutenant (platoon commander) in the United States Marine Corps.

[2] After serving three years in the Corps, Caputo began a career in journalism, joining the staff of the Chicago Tribune in 1968.

In 1973, Caputo was part of a writing team that won the Pulitzer Prize for reporting on election fraud in Chicago.

[4][5] Philip Caputo's memoir of Vietnam, A Rumor of War (1977), has been published in 15 languages, and has sold two million copies since its first publication.

The book was adapted as a 1980 two-part TV movie of the same name, starring Brad Davis, Keith Carradine, Brian Dennehy, and Michael O'Keefe.