Narrated in the first person by journalist Thomas Fowler, the novel depicts the breakdown of French colonialism in Vietnam and early American involvement in the Vietnam War. A subplot concerns a love triangle between Fowler, an American CIA agent named Alden Pyle, and Phuong, a young Vietnamese woman.

The novel implicitly questions the foundations of growing American involvement in Vietnam in the 1950s, exploring the subject through links among its three main characters – Fowler, Pyle and Phuong. The novel has received much attention due to its prediction of the outcome of the Vietnam War and subsequent American foreign policy since the 1950s. Greene portrays Pyle as so blinded by American exceptionalism that he cannot see the calamities he brings upon the Vietnamese. The book uses Greene's experiences as a war correspondent for The Times and Le Figaro in French Indochina 1951–1954. He was apparently inspired to write The Quiet American during October 1951 while driving back to Saigon from Ben Tre province, accompanied by an American aid worker who lectured him about finding a "third force in Vietnam".[2]

It was twice adapted as films, in 1958 and again in 2002.