With 14 Emmy Awards and an audience of over 100 million viewers, the TV show M*A*S*H helped the nation come to grips with the harsh and occasionally hilarious realities of war. Mobile Army Surgical Hospital 4077 was fictional, but the wisecracking main character Hawkeye Pierce was based on a real person: H. Richard Hornberger. But though the former U.S. Army Surgeon penned the book that led to the series—and was as heroic and humorous as Hawkeye himself—he came to hate TV’s take on his own creation.

Hornberger barely profited from the show—he only got $500 per episode, and sold the rights to the franchise for pennies. But his bitterness was more than financial. As the show’s reputation for its commentary on war grew, he distanced himself more and more from the series, and the character he modeled on his own wartime heroism and humor.

Hornberger’s books may have been whimsical, but his real-life war experiences were dead serious. Born in New Jersey in 1924, he struggled in his pre-med program and nearly didn’t get into med school until, according to biographer Dale Sherman, a chemistry teacher recommended him as “peculiar, but worth taking a chance on” to Cornell Medical School. Hornberger might have gone on to a normal career as a thoracic surgeon if not for the Korean War, which began in June 1950 when North Korea invaded South Korea.

A month later, the United States sent its first troops into South Korea as part of a battle against international communism. The war soon turned into a tense stalemate as truce talks between North and South failed again and again. Meanwhile, the United States began drafting soldiers—and doctors. That included just-graduated medical students and interns like Hornberger, who was drafted in 1951.

Hornberger soon found himself in Mobile Army Surgical Hospital 8055. The tent-based surgical hospital was one of seven fully functional, tent-based hospitals that operated at various points during the Korean War. The 8055 was located on the 38th parallel, which divides the Korean Peninsula and today serves as the demilitarized zone between North and South Korea.

The MASH concept was simple: The hospitals were located close enough to the front lines to serve wounded soldiers, but far enough away that they weren’t in danger of bombs or direct combat. Life in a MASH unit was grueling: Aside from the constant stress of warfare and long hours in surgery, the units usually picked up and moved at least once a month.

In Korea, Hornberger pioneered a kind of surgery that was prohibited during the war. “Hornberger possessed the courage and audacity to attempt arterial repair when it was forbidden, and by one account, he may have been the first,” writes Steven G. Friedman, a vascular surgeon who recently published an account of Hornberger’s daring surgical attempt.

At the time, it was against U.S. Army regulations for surgeons to do anything but close off a blood vessel in the case of an injury to the vascular system, or blood vessels. But the realities of war wounds made this intolerable to Hornberger and other surgeons who found themselves banned from repairing damaged arteries. In 1951, Hornberger’s colleagues tell Friedman, surgeons at the MASH unit decided that their Hippocratic oath to do no harm was more important than Army regulations and began to repair arteries despite the rules.

It is thought that Hornberger was the first to flout those rules—and scenes in his bestselling book back up the theory. When word got to other MASH units, doctors started doing arterial repairs there, too, and after the Korean War ended in 1953, doctors who dared to do the surgery helped further medical knowledge about how to repair human arteries and other blood vessels.

As for Hornberger, who went on to work in at the VA and in private practice, he dealt with the trauma he experienced during the Korean War by writing about it.

It took 12 years to write MASH: A Novel About Three Army Doctors, and another five years being rejected by publishers before the book was finally published under the pseudonym Richard Hooker in 1968. It was the perfect moment for a novel about war: the Vietnam War was looking more and more intractable and Americans longed for a lighter take on war.

The book was adapted to a hit movie and then a TV show that helped capture life in the unit. Like the books he wrote, it included a strong-willed head nurse, a Korean teenager whom the doctors sent to the United States for college on their own dime, and a doctor who dressed in drag at least once. And it helped capture the sarcasm and heart of Hornberger himself through Hawkeye Pierce, whose sarcasm and heart helped his friends and patients sustain operating conditions that were primitive and, often, nearly hopeless.

Though the show was ostensibly about the Korean War, it captured both the nation and Alan Alda’s disillusionment with the stalemate and human cost of the Vietnam War, largely through the cranky character of Hawkeye Pierce. The show helped the public deal with the emotional toll of Vietnam, and illustrated the harsh conditions of both conflicts for future generations. Eventually, viewers came to see the show as a kind of allegory for the Vietnam War.

Hornberger couldn’t have disagreed more. He hated the anti-war sentiments ascribed to him by the public. In 1983 he told a reporter for Newsweek that while the show was accurate in its physical portrayal of a MASH unit, it “tramples on my memories.”  And his son, William Hornberger, told the New York Times that his father hadn’t intended to write an anti-war book. “My father was a political conservative, and he did not like the liberal tendencies that Alan Alda portrayed Hawkeye Pierce as having,” he explained.

Today Hornberger’s book and television show define what many Americans know about both the Korean and Vietnam Wars—even though few know about the heroics its creator performed behind the scenes.