He began karting at the age of five where he won his first race by the time he was eight. Hauger won the ROK International title in the Mini category in 2014 then claiming Mini category titles in the Vega Winter Trophy, the Italian Karting championship, the WSK Champions Cup and the Super Masters Championships in 2015. That following year, Dennis became the youngest ever champion to win the DKM Junior Title.
Dennis entered the 2018 F4 British Championship in 2017 when he made his move to single seaters as a part of TRS Arden Junior Team with fellow Red Bull Junior Jack Doohan. He finished fourth in the overall standings with four victories, missing out on the Junior Championship to Doohan. He remained at the Formula 4 level for the 2019 season where he contested in the ADAC and Italian F4 Championships with Van Amersfoort Racing. During ADAC, Hauger claimed six victories where he finished as runner up to Théo Pourchaire. One of his victories was at the Formula One support race at the Hockenheimring. His luck was better in the Italian F4 as he scored himself twelve victories, including a weekend grand slam in the season finale at Monza where he claimed the title win.
Alongside the ADAC and Italian F4, Hauger made his debut in the Euroformula Championship in Silverstone with Motopark. He took home two consecutive fifth place finishes during the weekend.
FIA Formula 3
Hauger took part in the second and third days of the post-season testing in Valencia with Hitech Grand Prix before being announced as a member of the team in January 2020 by Red Bull. This year will be Dennis’ rookie year in FIA Formula 3.