Larry Heinemann, a Vietnam veteran who drew on his war experiences in two well-received novels — one of which, “Paco’s Story,” startled the literary world when it won the National Book Award for fiction in 1987 — died on Dec. 11 in Bryan, Texas. He was 75.

His daughter, Sarah Heinemann, said the cause was chronic obstructive pulmonary disease.

“Paco’s Story,” published in 1986, was an unexpected winner not only because Mr. Heinemann was not well known — he had published only one previous novel — but also because of the daunting competition it beat out. Other nominees that year included “Beloved,” by Toni Morrison (which won the Pulitzer Prize for fiction a few months later), and “The Counterlife,” by Philip Roth (which won the National Book Critics Circle Award for fiction). It had been widely expected that one of them would win the National Book Award.

“When Mr. Heinemann’s name was announced,” an account of the awards ceremony in The New York Times said, “a brief silence gripped the ballroom, followed by uncertain applause.”

Among those surprised was Mr. Heinemann himself, who had traveled from Chicago for the awards ceremony at the Pierre Hotel in Manhattan.