One of the most compelling American athletes of the 20th century died last week. Odds are that you have not heard of Dave Sime. He never played professional sports. He took more pride in his post-athletic career as a world-class eye doctor in Miami than anything he accomplished on the fields of play. His name wasn’t even pronounced the way it looks. Forget the “e” — Sime rhymes with him, not lime.

Some readers will remember his son-in-law, Ed McCaffrey, who as a wide receiver won three Super Bowl rings during the 1990s, two with the Denver Broncos and one with the San Francisco 49ers. An even greater number of football fans probably know of his grandson, Christian McCaffrey, the most electric all-purpose back in college last season, leading Stanford to the Pacific-12 title and a victory in the Rose Bowl.

But when David William Sime died of a heart attack at age 79, it brought to a close a singular life story that played out on the world’s stage. For a time in the mid-1950s, Sime was considered the fastest man in the world. He ended up with only one Olympic silver medal to his name, but if not for various misfortunes — an injury, the questionable ethics of a haughty West German opponent who beat him at the tape and the disqualification of a relay teammate — Sime might have won three golds, one in Melbourne in 1956 and two in Rome in 1960. And if not for what he considered the brusque, off-putting behavior of an intelligence agent at a restaurant on the Via Merulana, he might have returned from Rome with a more important prize, the defection of a Soviet athlete.

If his grandson can do it all in football, it was Sime who set the standard for all-purpose. As a 13-year-old from Fairview, N.J., he won a speed-skating contest at Madison Square Garden, an accomplishment that made the front page of the New York Daily News. This despite the fact that he hated to skate. He was so talented at football that he was recruited to play at West Point by an assistant coach named Vince Lombardi (and later drafted by the Detroit Lions).

His favorite sport was basketball, the game of his father, who had played briefly for the old Original Celtics based in New York. But when he enrolled at Duke University, it was not for football or basketball but to roam center field on the baseball team, and once at Duke, his raw speed led him to the track and national stardom in the dashes.

Dave Sime’s grandson, Stanford running back Christian McCaffrey, had a huge game against Iowa in the Rose Bowl on Jan. 1. (Mark J. Terrill/AP)

Sime taught himself the art of sprinting by reading every book on the subject in the university library. In the Jim Crow south, the big redhead often trained privately alongside the track stars at Durham’s historically black college, North Carolina Central, including its world-renowned hurdler, Lee Calhoun. After emerging from the 1955 Millrose Games with the fastest time in the world, he was favored to win gold at Melbourne but could not make the trip because of a leg injury suffered during the Olympic trials. By the time of the 1960 Games, he was 24 years old and being overshadowed on the American dash scene by Ray Norton, a heralded sprinter from California, but Rome offered him a final chance at glory.

Shortly before the U.S. team left New York for the flight to Italy, Sime received a call in his room at the Vanderbilt Hotel from a government agent, who persuaded him to accompany him to Washington that day for a clandestine meeting. The CIA had decided that Sime, who already was a medical student at Duke by then, was the perfect athlete to make an approach in Rome to Igor Ter-Ovanesyan, a Soviet long jumper from Kiev who had taught himself English and was known to love western books, movies and jazz. During the heat of the Cold War, he seemed like the likeliest athlete to bolt for the West if offered the opportunity.

The plan was for Sime to befriend Ter-Ovanesyan during the Games and set up a few dinners with him, after which a veteran agent would appear and close the defection deal. All went according to plan until the end of a second dinner at the Scoglio de Frisio, when the agent, known to Sime only as “Mr. Wolf,” arrived and started talking to Ter-Ovanesyan in his regional dialect. The Ukrainian long jumper, who already had won a bronze in Rome, was spooked by this and walked out of the restaurant with Sime. “David,” he said, “I don’t know if this guy’s a double agent or not, but I don’t really want to talk to him. I’m too scared.”

Events on the track at the Stadio Olimpico were even more frustrating for Sime. With Norton, the American favorite, undone by a debilitating case of nerves, it was left to Sime to battle Armin Hary of West Germany for the gold in the 100. Hary was a hustler who was surreptitiously taking money on the side from two German shoe companies, Puma and Adidas, and was considered so adept at anticipating the starting gun, or jumping it, that his nickname was the Thief of Starts.

In the final, after two false starts, Hary fired into the lead, but by the hallway point Sime was closing in on him with his long, erect strides, and they hit the tape almost simultaneously, Sime lunging so ferociously that he lost his balance and went sprawling onto the track. Both men were timed at 10.2 seconds, but photos showed that Hary won by at most an inch. A few days later, Sime seemed to get revenge on the West Germans, running anchor on the 4x100 relay, but he learned after hitting the tape first that his team had been disqualified when the luckless Norton took the baton too late on the second leg.

Rome marked the end of Sime’s track career. He returned to Duke, completed his medical degree and settled in South Florida, where he became such a renowned eye doctor that his clients included celebrities Ted Williams, Eddie Arcaro, the swimmer and actress Eleanor Holm and Nixon pal Bebe Rebozo. He also served as one of the physicians for the Miami Dolphins during the Don Shula era, when his main job was to help quarterback Bob Griese deal with various eye difficulties.

Sime was no saint. He loved to drink and tell stories, a foul-mouthed jokester. His first wife left him, and he had a difficult relationship with his children before he married his second wife, Illeana. But in his final years, as he battled cancer first in his eye, then his liver, then his lungs, he developed a relationship with his grandson and watched with swelling pride as Christian McCaffrey went from a high school star in Colorado to the national football stage at Stanford. They became texting buddies, and in his messages Sime called his grandson Snowball. He said that Christian was like a snowball rolling down a mountain, gathering momentum, growing larger, unstoppable.

Christian’s rise coincided with Dave’s demise. The old man had been in and out of the hospital from June through the fall months of the football season and died in the hospital Jan. 12 after suffering a heart attack. It was from his hospital room on New Year’s Day that he watched his grandson have his finest game, setting a Rose Bowl record of 368 all-purpose yards in Stanford’s 45-16 win over Iowa. Sime was rail thin by then. He had lost more than 20 pounds and could get fatigued just stepping out of bed. But for a few hours he was reborn, screaming so loud that the entire hospital floor could hear him. “He wanted to be everything at once,” Illeana said later of her husband. And now here was this amazing kid, Sime genes coursing through his blood, out there on the grass, in the California sunshine, being exactly that.

David Maraniss, an associate editor of The Washington Post, is the author of “Rome 1960: The Olympics that Stirred the World.”