French once set a record at the Ironman triathlon in Hawaii and is a five-time world champ in a sport he took up 25 years ago - just as he was helping American cyclist Greg Lemond win the Tour de France. French made the aerodynamic handlebars Lemond rode to victory in Paris in 1989.
But even at that, French is no ordinary athlete and he's had no ordinary life.
At 18, he was a machinist aboard the U.S. Navy ship that took Army Gen. Douglas MacArthur to the Battle of Borneo in 1945. In the 1960s, French appeared in ski films made in the Austrian Alps.
Just turned 84, he's been training for what will be easily his 200th triathlon.
When he donned his wetsuit and slipped into the Payette River in southwestern Idaho Saturday, it was a testimonial to human longevity and fitness. French doesn't consider it any special personal triumph, however.
"It's luck," he said. "I was fortunate to have a body where nothing goes wrong."
As for MacArthur, French wasn't that impressed.
Working below deck on the USS Cleveland, a light cruiser with a crew of 1,200, French helped fashion a set of ashtrays from artillery shells, a gift for the general. In return, MacArthur gave French and his shipmates a corn cob pipe.
"We threw it over the side," French said.
Watching French pedal his triathlon bike into the mountains around Sun Valley, it seems impossible that this man was born when Calvin Coolidge was president and the Great Depression was still three years off.
He still works 25 hours a month at Scott Sports, the Swiss-owned sporting goods maker with offices in Ketchum, near Sun Valley. After winning races, he leaps onto the podium. This summer, he was in France, cycling with buddies. He's headed to China this fall, for yet another bike tour.
"I'm living a life that's 15 or 20 years younger than I am," he acknowledges.
Hips and knees? All original parts.
"I'm the only guy I know who has hasn't had something replaced," said French, who lives with Marian, his wife of 40 years, on the Big Wood River a few hundred yards downstream from the house where writer Ernest Hemingway killed himself in 1961.
Ed Brockett, who runs the USS Cleveland Reunion Association from his home in Laguna Woods, Calif., didn't know French existed until a reporter called. Initially skeptical this octogenarian superathlete was a shipmate - "A lot of people say they were on the Cleveland," Brockett explained - he found photos taken in Tokyo Harbor in 1945.
C.S. French is on page 32, in the third row, second from left. His rank, Fireman 1st Class, no longer exists.
Brockett estimates 3,000 men served between 1942 and 1946 on the Cleveland, with the last reunion attended by only 11. None were doing triathlons.
"I am amazed, knowing all the aches and pains that I've got, how he does it," Brockett said.
French joined the Navy in 1944, in hot water with police for racing his homemade hot rod on Southern California streets. He was just 17, so his mom had to sign for him.
"She was glad to sign," he recalled.
French isn't sentimental, something he thinks might contribute to his physical condition.
"Some guys, they always live in the same place," he said. "I was always looking for something to do next."
After the war, French returned to California, getting a college degree in mechanical engineering.
He went to Europe with Douglas Corp. and Litton Industries, working on weapons contracts with the British and Italian governments. While based in Hamburg, Germany, in the mid-1960s, he'd take the Friday night sleeper train to Kitzbuhel, Austria.
There, a buddy from back home was shooting 16 millimeter films for the pioneering ski movie director Dick Barrymore. French, who moved to Sun Valley in 1970, still skis, often hiking up Sun Valley's Bald Mountain on climbing skins. Once on top, he sometimes rides the lifts - for free.
Don't tell the ski patrol, he whispered.
"I still ski bumps," he said. "I just can't ski for very long."
In 1971, French began as an engineer for Scott, working on ski boots, goggles and ski poles.
It was there that U.S. Alpine Ski Team coach, bike racer and inventor Boone Lennon showed up in 1986 with a wooden handlebar prototype that looked a bit like a toilet seat but put his body into an aerodynamic tuck.
French, then just 60, rode an early aluminum version at the 1986 Ironman triathlon in Hawaii, setting a record for his age of 12 hours, 13 minutes. Pro triathletes began calling, demanding their own handlebars.
"Guys who never could win before were winning," Lennon said in an interview from Bozeman, Mont. "People they beat would call, and week after week we would do more."
Finally, American champion Greg Lemond, coming off a shotgun accident that derailed his career in 1987, agreed to clip the bars to his 1989 Tour de France comeback bike. French personally bent Lemond's bars into shape in Ketchum.
Lemond entered the final stage, a time trial, with a 50-second deficit to rival Laurent Fignon. Many considered it impossible to overcome over just 15.5 miles, but Lemond beat Fignon by 58 seconds to take the overall win using what announcers called "unique and controversial handlebars."
"It's still the biggest timesaving thing you can do to a bicycle," French said, who has one of his aluminum bars on his carbon-fiber racing machine.
As of July 31, USA Triathlon had 44 members in its 80 to 89 age group, 38 men and 6 women.
But French - World War II vet, European ski bum, triathlete, witness to history - was the only one entered in Saturday's race in Idaho.
"Can you believe it? I go to a triathlon and I'm the only one in my age group, and I still get nervous," French said.