His American father, Greg Duplantis, is a former pole vaulter with a personal best of 5.80 m (19 ft 1⁄2 in), while his Swedish mother, Helena (née Hedlund), is a former heptathlete and volleyball player.

[12] His two older brothers, Andreas and Antoine, and his younger sister, Johanna, also took up sports; Andreas represented Sweden as a pole vaulter at the 2009 World Youth Championships and 2012 World Junior Championships, while Antoine dropped pole vault for baseball in high school before heading to Louisiana State University where he became the team's career hits leader in 2019.

[13][14] Duplantis graduated from Lafayette High School in 2018 and, like his parents and brothers before him, attended Louisiana State University, though he left in 2019 after his first year in order to turn professional.

His nickname stuck with him since then perhaps as an ironic foreshadowing of his world domination and record breaking performance in his sport later in his professional career.

[33][34] A month later, on 11 Mar, Duplantis improved his indoor personal record to 5.82 m (19 ft 1 in) in the same facility at the New Balance Nationals in New York City.

[38][39] The vault also became a Swedish senior record beating previous mark of 5.87 m set by Oscar Janson in 2003 by 3 cm (1 in).

[42]On 12 January, Duplantis began his 2018 season with an indoor personal record by clearing 5.83 m (19 ft 1+1⁄2 in) at the Pole Vault Summit in Reno, Nevada.

Although Duplantis submitted to a drug test administered by a USADA official, it was only done the next morning and not at the Reno-Sparks Livestock Events Center where the meet was held.

A year ago, Duplantis competed at the Texas Relays elite pole vault event wearing Lafayette High School colors only to find out later about a possible violation of the LHSAA rule.

In the process, Duplantis helped LSU Tigers win its first SEC Outdoor Track and Field Championship since 1990 edging Florida Gators 105–95.

[71] Duplantis was still tested by Piotr Lisek and Lavillenie's younger brother Valentin, who went on to claim bronze and silver respectively — the latter with a personal best.

[72] At the one-year delayed 2020 Summer Olympics in Tokyo, Duplantis won a gold medal when he cleared a height of 6.02 m (19 ft 9 in) on his first effort, and afterwards got very close to beating his own world record.

He compared the competition against Duplantis that evening as being a regular footballer "trying to emulate Lionel Messi or Cristiano Ronaldo" and that his superiority over the world's best pole vaulters was "impressive and ridiculous.

His winning height of 6.10 m (20 ft 0 in) represented not only his best ever season opener but also the highest season-opening performance of any pole vaulter in history.

[86] On 25 February at the All Star Perche indoor meeting in Clermont-Ferrand, France, Duplantis broke the world record again, clearing 6.22 m (20 ft 5 in) to increase the number of his career six-metre-plus jumps to 60.

[92] At the 2024 World Athletics Indoor Championships in Glasgow, in March, Duplantis made a vault of 6.05 m, winning the gold medal.

[102] Duplantis' uncanny ability to perform under pressure and to continually improve and break world record have solidified his status as a once-in-a-generation talent in athletics.

[103] The New York Times reported that Duplantis is to pole vaulting what Usain Bolt was to sprinting; Michael Phelps to swimming; Simone Biles to gymnastics.

[104] Duplantis' supremacy in the pole vault is so overwhelming that he often best his peers by almost a foot - a staggering gap considering medals are often won by margins of a centimeter.

[107] On 25 August, at the Kamila Skolimowska Memorial in Chorzów, Poland, the twelfth stop on the 2024 Diamond League, Duplantis improved his world record for the tenth time in his career and the third time in 2024 by one centimetre, increasing the world record to 6.26 m.[108][109] The men's pole vault event at the Silesian Stadium saw two other jumpers (Sam Kendricks of the US and Greece's Emmanouil Karalis) cleared six metres besides Duplantis making it the first time in history that three pole vaulters broke the 6.00 m barrier in a single competition.

In one of the most remarkable moment in track and field history, Jakob Ingebrigtsen shattered the longest-standing men's athletics world record in an individual event, clocking a staggering 7:17.55 for the 3000m, taking more than three seconds off the mark of 7:20.67 set by Kenya's Daniel Komen in 1996.

Duplantis turned out to be the historic first MVP of the meeting and took home a sparkling 14-carat gold diamond-encrusted 'Champion Ring' worth $10,000, along with a cheque for the same amount.

[110] On 4 September, the day before the Zürich Diamond League, Duplantis competed in an exhibition 100 m event against 400 m hurdles world record holder Karsten Warholm.

[111][112] On 13 September, Duplantis rounded off his stellar 2024 campaign with a fourth consecitive Diamond League trophy at the 2024 Final in Brussels, winning the competition with a meet record of 6.11 m.[113] On 26 Oct, Duplantis was crowned men's European Athlete of the Year for the first time outright having previously shared the award with Jakob Ingebrigtsen in 2022.

[114] On 6 November, Duplantis joined a network of sports stars such as Brazilian footballer Neymar Jr and Norwegian hurdler Karsten Warholm to become global ambassabor for the Wings for Life World Run charity event to be held on 4 May 2025 to raise funds for spinal cord injury research.

[122] Encouraged by his mother, Duplantis took extensive lessons over Skype in order to improve his Swedish language fluency, and by 2020, felt that he understood native speech much better and faster than he could in the past.

His mother claimed at the same time that while Duplantis felt shy about speaking Swedish in public, he was very happy to do so in private, where there was less pressure.

[123][124] By 2021, after winning Olympic gold in Tokyo, his knowledge of the language had improved to the point that he felt comfortable giving interviews fully in Swedish.

[126] Duplantis usually divides his year between winters in Louisiana and summers in Uppsala in Sweden, adapted for when the two climates offer the best possibilities for training.

[127] Duplantis is currently dating Swedish model and content creator Desiré Inglander, whom he met at a midsummer party in Sweden in 2020.