[2] His family's wealth made it possible for Rahe to focus on leisure activities like playing tennis or driving expensive cars.

In 1906, at the German open championships, he could reach the final but lost to Josiah Ritchie in straights set, winning only 5 games.

[3] In 1913 he was runner-up at Wimbledon, losing the men's doubles final together with Heinrich Kleinschroth in four sets against the defending champions Herbert Roper Barrett and Charles P. Dixon.

At the beginning of World War I, Rahe joined the German army and was assigned to the Kaiserliches Freiwilliges Automobil-Corps at the headquarters of the crown prince.

[2] Rahe's last appearance as a tennis player was at the 1941 German senior championships, where he reached the final but lost to Max Hopfenheit.