Pro football may be, as many pundits claim, our national sport, but it has created very little in the way of genuine memories. More Americans watch the Super Bowl than any other sporting event, but very few of the players make an impression on today’s sports fans. As the Giants Hall of Fame linebacker Sam Huff points out in Tom Callahan’s book “Johnny U: The Life and Times of Johnny Unitas” (Crown, 304 pages, $25), 15 Hall of Famers were on the same field during the televised era’s first great game, the 1958 sudden death clash between the New York Giants and Baltimore Colts. “From last year’s Super Bowl,” says Huff, “can you name fifteen players? Today you don’t know who’s playing for who.” And of all the players on the field, “Unitas was the master.”

Unitas was the National Football League’s first household name, the first pro football player to be recognized on a level with Mickey Mantle and Willie Mays. Modern pro football is practically dated from his first championship season in 1958. Amazingly, half a century after Unitas began his professional career, Mr. Callahan, a sports columnist for the Washington Post, has written the first book to tell us how and why Unitas kickstarted a legend. Mr. Callahan’s writing is appropriate to his subject, lean and unpretentious and to the point. Like Unitas, he rises to the occasion in the big games. Those never fortunate enough to watch Unitas play will feel as if they have to clean grass stains off their pants after reading this book.

John Constantine Unitas was born in Pittsburgh in 1933 and raised by his Lithuanian immigrant mother after his father died when John was 5. He was born working class and stayed that way. At the height of his fame, gossip columnist Louella Parsons, who made a living from champagne-fueled conversation with Cary Grant and Clark Gable, sought an interview. “Sure, Louella,” he told her, “sit your ass down and let’s have a beer.” Parsons fled.

Like most great stars of his generation, Unitas used football as a ticket out of a life of factory labor. His high school coach, Max Cary, taught him that “a quarterback can’t just be one of the boys. … You can sit with them. You can have a joke. You can have a drink. But you always have to keep a certain distance.” He developed such mental tenacity that, according to one of his All-Pro receivers, John Mackey, “Playing with Johnny Unitas was like being in the huddle with God.” But not right away. After failing to gain a scholarship from Notre Dame and Pittsburgh, he had an up-and-down college career with the disorganized Louisville program. Upon graduation, no one wanted him; he was finally taken in the ninth round, and he earned a shot with the Baltimore Colts only after being dumped by the Pittsburgh Steelers.”Cutting Unitas,” writes Callahan, “would become the Steelers’ signature blunder.”

Unitas came of age when the passing game was capturing the imagination of television viewers and when quarterbacks, not a brain trust of coaches, called their own plays. From the late 1950s to the NFL merger in 1970, the game was played by men whose names now sound mythical — men like Jim Brown, Alex Karras, Y. A. Tittle, Frank Gifford, and Unitas’s great friend and rival, Green Bay Packers quarterback Bart Starr — men who were paid not much better than Wal-Mart employees today. “The time,” Mr. Callahan writes, “was different. The players lived next door to the fans, literally. There wasn’t a financial gulf, a cultural gulf, or any other kind of gulf between them.” With his laser-like passing skill and riverboat gambler’s flair, Unitas helped change all that by ushering football into the big-money TV era.

When the game changed, becoming glitzier and more sophisticated, Unitas stayed the same. He never felt the need to unburden himself to the public. When a sportswriter dryly inquired if he had written his own autobiography, he replied, “Hell, I didn’t even read it.” When the Pro Football Hall of Fame asked him for his memorabilia, he gave everything but his shoes. “They’re great for cutting the grass,” he said. That grass didn’t grow in Indianapolis. When Colts owner Robert Irsay sneaked the franchise out of Baltimore in the middle of a night in 1984 — football’s equivalent of the Brooklyn Dodgers moving to Los Angeles — Unitas requested that his statistics be removed from the Indianapolis record book. His explanation was simple, “I never played there.” One hesitates to call it a curse, but the Colts haven’t won a championship since they left Baltimore.

Mr. Barra last wrote for these pages about Bear Bryant.