The Somerset driver, who won the 2009 F1 title for Brawn GP, will drive for his own JBXE squad in the new electric off-road SUV series, which is due to begin in Saudi Arabia on 3/4 April.
Each outfit in Extreme E must field a male and female driver to share a 550bhp off-road buggy, and Button’s team-mate has yet to be named.
Since his final F1 season in 2017, Button has competed in a range of motorsport categories, winning the Japanese Super GT title in 2018 and making appearances in the World Endurance Championship.
Last year, he co-founded a British GT team, Jenson Team Rocket RJN, for which he competed in the season finale at Sivlerstone. He also recently became a special adviser to the Williams F1 team.
Button has tackled a number of off-road events, too, including the long-running Baja 1000. His late father John was a leading rallycross driver in the British championship in the 1970s and 1980s, and he has long expressed a desire to take in more off-road competition.
“JBXE has been a long time coming, and I'm both delighted and proud to announce its formation and entry into the inaugural Extreme E Championship,” said Button. “I caught the off-road bug a few years back, which led to me entering my own team in a few races, including the Mint 400 and even the Baja 1000, and I absolutely loved it.”
Button is the third F1 champion to take ownership of an Extreme E squad, joining seven-time title-winner Lewis Hamilton and 2016 winner Nico Rosberg.
Extreme E boss Alejandro Agag, founder and CEO of Extreme E said: “Jenson, alongside his peers, will give further weight to our mission to raise awareness of the global climate crisis, while doing what we love: racing.”