Mr. Browne went to Vietnam in 1961 as the Saigon bureau chief of the Associated Press and was one of the first reporters to cover the growing conflict that would ultimately claim more than 50,000 U.S. lives.
He chronicled the regime of South Vietnamese President Ngo Dinh Diem and the homegrown opposition led by Buddhist monks. On June 11, 1963, Mr. Browne was present when an elderly monk named Thich Quang Duc, wearing sandals and a robe, calmly sat cross-legged on a cushion in the center of an intersection in Saigon.
Other monks poured fuel over him, and the monk struck a match and was immediately engulfed in flames. Mr. Browne shot roll after roll of film, documenting the self-immolation.
“Everybody that witnessed this was horrified,” Mr. Browne said in a 2011 interview with Time International. “It was every bit as bad as I could have expected. The main sound was the wailing and misery of the monks, who had known this guy for many years before and were feeling for him.”
Afterward, he sent the film with a passenger on a commercial flight to Manila. When the AP made the graphic images public, the sense of shock was felt around the world.
“The picture he took was the equivalent of going viral today,” William Prochnau, author of “Once Upon a Distant War: Young War Correspondents and the Early Vietnam Battles,” said Tuesday. “As soon as he got it out of there, it was in every paper in the world.”
Mr. Browne’s photograph drew unprecedented attention to U.S. involvement in Vietnam. Within months, the administration of President John F. Kennedy abandoned support for the Diem regime, which collapsed Nov. 1, 1963, when Diem and his brother, Vietnamese security chief Ngo Dinh Nhu, were overthrown and killed in a U.S.-supported coup.
In the meantime, Mr. Browne continued reporting on the escalation of U.S. military operations in Vietnam, sometimes smuggling his stories out through couriers. When he tried to photograph U.S. pilots flying combat missions, in violation of their official non-combat roles, his camera was seized.
A Navy admiral, annoyed by Mr. Browne’s persistent questioning, once asked him, “Why don’t you get on the team?”
In 1964, Mr. Browne shared the Pulitzer Prize for international reporting with David Halberstam of the New York Times.
His photograph won international awards but not the Pulitzer, which was awarded to Robert Jackson of the Dallas Times Herald for his image of Jack Ruby fatally shooting Lee Harvey Oswald. Nonetheless, Mr. Browne’s photo remains one of the most powerful images of a war that continues to reverberate in the national memory.
“His magic moment was the picture,” Prochnau said of Mr. Browne. “I think, without any doubt, it laid the groundwork for a lot of the opposition that came afterward. It told the administration that they just couldn’t win under Diem, that he didn’t have control of his country.”