In 2016, he produced a wet-weather masterclass to take his maiden MotoGP victory at Assen and claimed multiple podiums with satellite (second-tier) Ducati Team Pramac Racing from 2017-2020. 

Jack became a Factory Ducati MotoGP Rider when he was promoted to the Ducati Corse and took his momentum from the 2020 season and went to a new level in 2021, matching his 2019 haul of podium finishes (five), finishing a career-best fourth in the world championship, and – most impressively – taking two race victories, which came at consecutive Grands Prix in Spain and France, the Le Mans race showcasing his trademark pace in sketchy conditions that made for a flag-to-flag GP. His Saturday speed was formidable too; Jack qualified on the front row eight times, five of those appearances coming in the final six races of the year, and he signed off 2021 in style with back-to-back third-place results in Portugal and Valencia. His haul of 181 points was a new season-high, and helped Ducati win both the teams’ and constructors’ titles.

The 2022 season would be the last year spent at Ducati Corse after Jack signed with KTM Red Bull Factory Racing from 2023. In his final year in red, Jack finished fifth in the World Championship despite achieving a career high 7 podiums & 189 points, including victory in Japan and earning Pole Position in San Marino. Additionally, Jack would contribute to Ducati earning its third World Constructors Championship in a row.