René Madsen made his professional debut in 2017 as a player for the Reason Gaming team, where he won bronze medals at the Gfinity Elite Series UK - Season 2 tournament. In 2018, he transferred to GoldenGitte and later to Squared Esports; however, Rene did not achieve significant success with these teams.
In the summer of 2019, Madsen signed with OpTic, where he clinched victory at DreamHack Open Summer 2019. The following year, he secured gold with the team at the United Masters League Season 2.
Since August 2020, TeSeS has been representing the HEROIC team and continues to play for them in 2024. During his time with HEROIC, the esports athlete has won numerous tournaments, including ESL One: Cologne 2020 Online - Europe, ESL Pro League Season 13, PGL Major Antwerp 2022: European RMR A, Pinnacle Cup Championship, BLAST Premier: Fall Finals 2022, and BLAST Premier: Spring Final 2023. He also earned silver medals at the Intel Extreme Masters Rio Major 2022 and Intel Extreme Masters Katowice 2023.