Joe Galloway, a war correspondent whose wrenching account of the first major battle of the Vietnam War was the basis for the book “We Were Soldiers Once … and Young,” which became a best seller and the basis of a hit movie, died on Wednesday in Concord, N.C. He was 79.

His wife, Dr. Grace Liem, said the cause was complications of a heart attack.

Mr. Galloway started in journalism at 17 and worked for 22 years as a war correspondent and bureau chief for United Press International. He was the only civilian awarded a medal of valor by the Army for combat action in the Vietnam War.

He later wrote for U.S. News & World Report and for the Knight-Ridder newspaper chain. He played a vital role in the skeptical reporting by the chain’s Washington bureau about the George W. Bush administration’s claims that Iraq had stockpiled weapons of mass destruction, claims the administration used to justify the American invasion of Iraq in 2003.

“He hates war, and he loves soldiers,” Lewis Lord, a former colleague at U.S. News, told the Military Writers and Editors Association when it honored Mr. Galloway in 2006 on his return to his home in Texas from his reporting base in Washington.

In the foreword to “We Are Soldiers Still,” a sequel to “We Were Soldiers,” General H. Norman Schwarzkopf, who led allied forces during the 1991 Persian Gulf war, called Mr. Galloway “the finest combat correspondent of our generation — a soldier’s reporter and a soldier’s friend.”

Mr. Galloway, who carried a weapon while covering the Vietnam War as a U.P.I. correspondent, was embedded with American troops during the four-day battle of Ia Drang, in the jungle of the Central Highlands, which began a day after his 24th birthday in 1965. He was awarded a Bronze Star Medal with the “V” device, denoting heroism, for rescuing wounded soldiers under fire during the engagement.

Both sides claimed victory, with the United States convinced it could win a war of attrition and North Vietnam confident it could withstand whatever technological advantage the Americans wielded over Vietnamese guerrillas.

The U.S. troops were commanded by Harold G. Moore, then a lieutenant colonel and later a lieutenant general, with whom Mr. Galloway would collaborate on “We Were Soldiers Once … and Young.” The book was published in 1992 and adapted 10 years later into the Randall Wallace film “We Were Soldiers,” starring Mel Gibson, in which Barry Pepper played Mr. Galloway.

Nicholas Proffitt wrote in The New York Times Book Review that “We Were Soldiers Once … and Young” was “a car crash of a book; you are horrified by what you’re seeing, but you can’t take your eyes off it.”

Mr. Galloway and Lieutenant General Moore published “We Are Soldiers Still: A Journey Back to the Battlefields of Vietnam” in 2008.

Articles by Mr. Galloway reconstructing the battle, which became the basis of the first book, won a National Magazine Award for U.S. News & World Report in 1991.

As a result of Mr. Galloway’s critical coverage of the run-up to the Iraq war, Defense Secretary Donald H. Rumsfeld summoned him to a meeting with high-ranking officers and accused him of relying on sources who were retired and out of the loop. As John Walcott, a colleague of his at U.S. News, Knight Ridder and McClatchy (which bought Knight Ridder), recalled, Mr. Galloway startled the group by declaring that some of his sources “might even be in this room.”

He later admitted that he only said that to rattle the assembled military brass, and that “it was fun watching ’em sweat.”

Mr. Galloway was an author, along with other U.S. News staff members, of “Triumph Without Victory: The Unreported History of the Persian Gulf War” (1992). His coverage of the later Persian Gulf conflict was portrayed in Rob Reiner’s film “Shock and Awe” (2017), in which Tommy Lee Jones played Mr. Galloway.

Joseph Lee Galloway Jr. was born on Nov. 13, 1941, in Refugio, Texas, to Joseph Galloway Sr. and Marian (Dewvell) Galloway. His father worked for Humble Oil.

Less than a month after he was born, the Japanese attacked Pearl Harbor. Four of his mother’s brothers went to war; so did his father and five of his brothers.

“I did not meet my father until the end of 1945, when he came home from the service,” Mr. Galloway said in an interview seen on C-SPAN. “My earliest memories,” he added, “are of living in houses full of frightened women looking out the window for the telegraph boy.” He was so affected by the war, he said, that he decided to become a war correspondent.

He was hired by The Advocate in Victoria, Texas, when he was 17, joined U.P.I. at 19 and was bureau chief or regional manger in Tokyo, Jakarta, New Delhi, Singapore, Moscow, Los Angeles and Vietnam, where he served four stints.

In addition to Dr. Liem, whom he married in 2012, he is survived by two sons, Joshua and Lee, from his first marriage, to Theresa Magdalene Null, who died in 1996. (His second marriage, to Karen Metsker, ended in divorce.) He is also survived by a stepdaughter, Li Mei Gilfillan; three grandchildren; and two step-grandchildren. He lived in Concord.

Mr. Galloway acknowledged that when he arrived in Vietnam, most of what he knew about war he had learned from John Wayne movies, but he understood the need for accuracy in a combat zone. “You really don’t want to screw up a story about men who are armed and dangerous and who you will likely see again,” he said in an interview with historynet.com.

He was also torn about reporting his doubts about American prospects for an honorable exit strategy.

“I thought, ‘This war we can’t win, but I’m not going to say that, because I don’t want to hurt my friends, the soldiers who are fighting this war.’” he recalled. “You know the one thing about soldiers is that if they are in combat and they are losing their friends and buddies, you can’t tell them that they died for nothing. You can’t say that; you wound them, you hurt them, you damage them. And that I could not do.”

Still, he said, he wished he could have “written a story so powerful about that battle” that it would have driven President Lyndon B. Johnson to withdraw.

Mr. Lord, his former colleague, described Mr. Galloway as “a most unlikely antiwar activist — a big, blunt Texan, proud to bear arms, as politically incorrect as he could be, full of unprintable epithets and anecdotes.” But, he added, Mr. Galloway “had a heart as big as his home state, a superb intellect that shone mischievously through smiling Irish eyes, and an openness that made it possible for him to conclude that it was an unpardonable sin to send young Americans to fight meaningless wars.”

Mr. Galloway’s view of war came through when he responded to criticism from the Pentagon after he profiled a retired Marine general who had critiqued Mr. Rumsfeld’s conduct of the Iraq war.

In an email exchange, Mr. Rumsfeld’s spokesman maintained, “We’re all hard at it, trying to do what’s best for the country.” So was he, Mr. Galloway replied, during four decades of covering America’s valiant warriors.

“Someone once asked me if I had learned anything from going to war so many times,” Mr. Galloway told the Pentagon spokesman. “My reply, ‘Yes, I learned how to cry.’”