Beginning karting for fun after breaking his leg on a bike, Jack advanced to racing competitively and claimed multiple State Title Wins in Australia and impressed at the World Karting Titles. 

Jack moved overseas to follow his dream of driving in Formula 1 and took a massive step-up into the British Formula 4 Championship where he claimed a podium on his debut and later finished 5th overall, as well as securing the Rookie Cup. 

Jack then advanced to racing in the Euroformula & Asian Formula 3 Championships concurrently where he claimed multiple podiums and race wins in each. Jack entered a second season of the Asian Formula 3 Championship after finishing runner-up but was robbed of the 2019 Championship when tyre failures plagued him in the final round and he was unable to finish two races. 

In 2020, Doohan signed with HWA RaceLab for the FIA Formula 3 Championship but struggled with technical issues and regular collateral damage on track. 

Jack was rejuvenated in 2021, making the switch to join Trident for his second season of F3, winning 4 times and notching an additional 7 podiums in a breakthrough year as one of the strongest championship challengers, ending the year as vice-champion and leading Team Trident to F3 Teams’ Championship success.

Jack announced he would racing for Virtuosi Racing in the 2022 FIA Formula 2 Championship, marking his first full year in F2. Heading into the last round of the season Jack was sitting 4th overall but was forced to retire from the lead in the feature with a loose wheel and dropped to 6th in the Championship. Jack wrapped up his 2022 commitments by driving for Alpine in the one-day post-season F1 test and then completing a three-day F2 test at the Yas Marina Circuit immediately afterwards, topping the timesheets on the second day.

Jack raced his first full-time season in F2 for Virtuosi Racing and heading into the last round of the season Jack was sitting 4th overall but was forced to retire from the lead in the feature with a loose wheel and dropped to 6th in the Championship. 

In 2023, Jack was announced as the Alpine F1 Team Reserve Driver and confirmed he would return to F2 again with Virtuosi Racing to fight for the title.