TOKYO — Mondo Duplantis took his first pole vault with a broomstick. He was 2 or 3 years old, and he hoisted himself onto the family couch in the living room of his family’s home in Lafayette, La. Fear is the first benchmark for a pole vaulter: If you feel any, even at the start, it is not for you. Duplantis never felt any fear.

Duplantis, 21, took his latest pole vaults Tuesday night at National Stadium, and it served as an expression of the genius he has honed since childhood. He grazed the bar with his chest on one of them with the bar set at 6.19 meters (20 feet 3¾ inches) — higher than anyone has ever cleared. He could not break his own world record, so he settled for a gold medal with a vault of 6.02 meters (19-9), in front of American silver medalist Chris Nilsen’s 5.97 (19-7).

Duplantis may be the greatest track and field athlete competing this week, in the conversation with Norwegian hurdler Karsten Warholm, Dutch distance expert Sifan Hassan and American hurdler Sydney McLaughlin. Duplantis grew up in Louisiana and competed for LSU, yet he jumps wearing the yellow of Sweden, a nation he did not set foot in until adolescence.

Duplantis — given name: Armand — had brought athletic glory to the nation of his mother’s birth even before his gold. On Feb. 8, 2020, Duplantis set the world record at 6.17 meters (20-3) in Torun, Poland. He broke it again a week later, nudging it to 6.18 meters (20-3¼) in Glasgow.

“When it comes to Mondo, you’re almost working with your imagination,” said six-time American pole vault champion Sam Kendricks, whose positive coronavirus test knocked him out of these Games. “What can he do, and how can you match him? Mondo Duplantis actually made me the world’s greatest loser. When we were in Lausanne, Switzerland, last year, I jumped higher than any man had in history to get second place.”

If an experiment had been conducted with the aim of building the greatest pole vaulter ever, it would have looked something like the combination of Duplantis’s genetics and upbringing. His parents, a Cajun named Greg and a Swede named Helena, met on the LSU track team. Greg pole-vaulted at the 1996 U.S. Olympic trials, and Helena competed in the heptathlon and played volleyball at LSU.

In 1993, the Duplantises had their first child, Andreas. He took an early interest in pole vaulting, so Greg built a vaulting pit in the backyard. It was not much at first. It was small, and the runway was dirt.

By the time Mondo came along, it became something out of a sports-loving child’s dream. When LSU sold an old indoor track at auction, Greg bought it for about $10,000 — pennies on the dollar — and turned it into a pole vault runway. He installed a regulation pit. Aside from the vaulting setup, the Duplantises erected a batting cage, a trampoline, monkey bars, a climbing rope and a chin-up bar in the backyard.

“We got some very good neighbors,” Greg said. “They probably think we’re a little odd.”

Mondo also loved baseball. Andreas played on a team that went to the Little League World Series. Mondo and Antoine, the family’s middle son, traveled to watch him and became intensely motivated to play in Williamsport, Pa., themselves. Mondo barely touched a pole when he was 12 years old. Antoine now plays outfield for the Brooklyn Cyclones, the High Class A affiliate of the New York Mets.

Mondo returned to pole vault. Greg would walk upstairs late at night, open the door to his son’s room and see him studying pole vaulters on his iPad. The next day, Mondo would head to the backyard and emulate the styles and techniques he studied.

“It’s really an event where you look at somebody, and they do it or they can’t do it,” Greg said. “You could tell he could do it.”

Greg could tell Mondo had no fear, possessed inherent kinetic grace and loved the sport enough to work at it. It became a matter of how tall he would grow. Pole vaulters who are too short lack leverage to clear the highest bars, and pole vaulters who are too tall lack coordination to execute the aerobic maneuvers at the top of a jump. There are some great pole vaulters who stand an inch shorter than 6 feet or taller than 6-foot-3, but not many. Duplantis settled at 6 feet.

By the time Mondo turned 15, Greg knew he would be special. Mondo then faced the decision of which nation to represent.

“I’d like to say it was some grand plan that we had,” Greg said. “But it wasn’t.”

In the summer of 2015, Duplantis wanted to compete at the under-18 championships in Cali, Colombia. The Swedish national team coach contacted Greg and started “hammering me,” Greg said. Even though Duplantis had lived only in the United States, his mother gave him Swedish eligibility. And Sweden wanted him.

The coach told Greg that Sweden would make him a coach. Mondo could jump for Sweden at the under-18 championships without having to qualify at the trials, as he would in the United States. At 15, competing with U.S. vaulters two years older, that was no guarantee. The offer was enticing.

“My wife wanted him to compete for Sweden,” Greg said. “Of course, I was leaning toward the United States. But I didn’t feel that strongly about it.”

Mondo chose Sweden. It did not feel like a rejection of his home country. It felt like an embrace of his mother.

“It’s just kind of half my blood,” he said. “I just chose one half over the other.”

Duplantis believes he made the right choice. He lives in Sweden now, which makes it easier to compete at European meets. He receives financial and fan support from Sweden that he would not in the United States. “I love being a Sweden athlete,” he said.

It also has given him a measure of fame that would have been unfathomable in the United States — something close to the LeBron James of Sweden.

“He’s close,” Greg said. “He can’t go anywhere without being recognized.”

Despite the fame, Duplantis carries himself with nonchalance. After he qualified over the weekend, he explained his plan: recovery and playing FIFA. U.S. sprinter Sha’Carri Richardson, who teamed with Duplantis at LSU, called him one of her best friends.

“He’s cool people,” said U.S. Olympic high and long jumper JuVaughn Harrison, who roomed with Duplantis at LSU. “People think he’s some stuck-up, big celebrity. He’s really cool.”

In Tokyo, he maintained his cool. Surrounded by Swedish media members after his qualification, Duplantis discussed his performance, laughing off the rare bar he missed at 5.50 meters (18-0½).

“I feel chill,” Duplantis said. “It’s an important moment for me. Basically, my whole life has built up to this moment. I’ve wanted to be here since I was 3 years old, jumping out of my parents’ backyard. If there is a moment I would be stressed out, it would be now.”

Duplantis showed Tuesday night, and maybe he already knew, that there was nothing to fear.