Peter Gent, 69, a onetime wide receiver with the Dallas Cowboys, whose 1973 novel, “North Dallas Forty,” exposed the drug use, hypocrisy and pervasive pain in the life of a pro football team, died Sept. 30 at his home in Bangor, Mich. His son told the Associated Press that Mr. Gent died of a pulmonary ailment.

Six years after his novel was published, Mr. Gent wrote the screenplay for a popular film, which has become a classic of sports cinema.

The book and film were widely denounced by the National Football League establishment at the time, but Mr. Gent’s depiction of the pain-ravaged lives of players has come to be seen as stark realism. Sports Illustrated named “North Dallas Forty” one of the greatest sports books of all time.

Mr. Gent, who was a college basketball star at Michigan State, entered the NFL in 1964 without having played a single down of college football. He said he tried out for the Cowboys because he was promised $500 if he went to training camp.

He made the team and became a 6-foot-4 wide receiver with sure hands and the ability to take a hit from defenders. The best of his five seasons came in 1966, when he caught 27 passes for an average of 17.6 yards per reception.

Five years after his final game, Mr. Gent made a more lasting mark on football with “North Dallas Forty,” which chronicles eight days in the lives of the players and coaches of the North Dallas Bulls.

The book was fiction but was clearly drawn from Mr. Gent’s experiences in the exhilarating but ruthless world of pro football. He broke his back in one game, and his nose was fractured or dislocated 14 times.

Mr. Gent was easily recognizable as an aging receiver named Phil Elliott (played by Nick Nolte in the film), and quarterback Seth Maxwell (Mac Davis in the movie) was clearly modeled on the Cowboys’ charismatic Don Meredith, who died last year.

In “North Dallas Forty,” the players soothe their injuries and anxious souls with booze, pills and over-the-edge antics. One of the ironies of the book is that players are pumped full of painkillers but are seen as moral degenerates for smoking marijuana.

Describing his callous treatment by the team, Mr. Gent’s stand-in, Elliott, says, “I was like leather dried in the sun.”

When the book was published, sports journalist Stephen Singer wrote in The Washington Post that “the book is without question the definitive rendition of what life is really like” in the NFL.

Sportswriter Dick Schaap wrote in the New York Times that Mr. Gent “balances shock with humor, irony with warmth, detail with insight, and ends up with a book that easily transcends its subject matter.”

Mr. Gent’s literary efforts were not so well received by his former team in Dallas. Tex Schramm, the Cowboys president, called the book “a total lie.”

“What has happened is one person, who in my opinion has a sick approach to life,” he told The Post in 1973, “has indicted the whole NFL and the Dallas Cowboy organization. . . . I consider the book offensive and malicious.”

Mr. Gent said he suffered many lasting physical and psychological effects from his football career.

“I do know this,” he told The Post in 1979. “During the first couple of years after I left football, there was no justification for living. It was a nightmare. Life just had no meaning compared to catching a football.”

George Davis Gent was born Aug. 23, 1942, in the rural town of Bangor. Mr. Gent, who was known as “Pete” during his athletic career, led his high school basketball team to a state championship and was a three-year starter at Michigan State. As a senior, he led the Spartans in scoring, averaging 21 points a game, and after graduating, he was drafted by the Baltimore Bullets of the National Basketball Association.

On a lark, he tried out for the Cowboys, although he hadn’t played football since high school.

Mr. Gent worked in advertising before turning to writing, and he published a sequel, “North Dallas After 40,” in 1989, as well as other novels about football and basketball. In 1996, he published a well-received memoir, “The Last Magic Summer,” about being a single father coaching his son’s baseball team. He had lived in his home town of Bangor since 1990.

His two marriages ended in divorce. Survivors include two children and a brother.

In a 2004 interview with NPR, Mr. Gent said that, in spite of the damage caused by football, “there were very few things in your life after that that were as exciting or as intense.”

“It’s like a world that nobody can imagine,” he said, “but as long as the game is there, you know, like I said, I’d do it again.”