Rühr played in his childhood as his 3 older siblings at Kahlenberger HTC, he played in the youth of Uhlenhorst Mülheim for 10 years and in the 2014–15 season in Hamburg for Club an der Alster for one year. He was voted "talent of the world" in January 2014, moved to Rot-Weiss Köln in 2015 and won the German field hockey championship in his first season with the Cologne team. In January 2016, he was voted the "Rising Star" (Best Youth Player of the World) for the second time. On 28 May 2021, he was named in the squads for the 2021 EuroHockey Championship and the 2020 Summer Olympics.