Rosenqvist started racing single-seaters in 2007 after a relatively short karting career, ending up third in the 2017 Chinese Formula Renault. In the same year, he entered selected other races, and continued with Formula Asia 2.0 in 2008, dominating the season. In 2009, he took part in the Northern Formula Renault championship, becoming driver champion, and he also claimed the Swedish Formula Renault title that year. In 2011 he won the RTL Masters of F3 event and cruised to his first Macau Grand Prix win in 2014. After scoring several wins in European Formula 3, he joined PREMA to dominate the 2015 season, claiming his second Macau GP in the process. The following years saw him enter GT, sportscars, and Indy Lights events. From 2016 to 2019, he raced for the Mahindra Formula E team and scored three wins, but he also had time to rejoin PREMA at Macau one final time. Since 2019, he has been competing in IndyCar, at first with Chip Ganassi Racing and then with McLaren. He claimed his maiden win in 2020.