Initially cut by French professional football team Stade Français, Raoul Diagne signed at the age of 16 with Racing Club de Paris.

A tall, elegant, and versatile defender who was excellent in the air, Diagne was the first black player to be selected for the France national team.

The French press nicknamed Diagne the "Black Spider", given his impressive height (1.87 m) and limb reach.

In fact, it was not uncommon to see Raoul exchange his position with the actual right winger in order to seek a result at the end of the game.

At the end of the 1940s, after finishing his playing career in Toulouse (until 1942), Annecy (1942–1945) and Nice (1945–1947), he obtained his coaching diplomas and practiced in Belgium, Algeria, and Normandy.