Despite many successes in Grand Prix motor racing for Auto Union in the early 1930s, during the era of the famous "Silver Arrows", he is now mostly known for his domination of hillclimbing, which earned him the nickname "Bergkönig" or "King of the Mountains".

Stuck's experience with car racing started in 1922 with early morning runs bringing milk from his farm to Munich, shortly after his first marriage.

With his experience from racing up mountain passes in the Alps in the 1920s, he was virtually unbeatable when he got the new Auto Union car, which was designed by Porsche.

After Stuck missed a number of hill-climbs because of injuries suffered in accidents, that year the European Mountain Championship fell to his famous team-mate, Bernd Rosemeyer.

1938 opened poorly; Stuck was either fired from, or quit, the Auto Union team (accounts from the two sides differ).

After a series of injuries to other team drivers, as well as pressure from the German government (again, accounts differ as to what combination of factors was the cause), he was re-hired, and proved himself by winning a third European Mountain Championship, his last major pre-war success.

A link with Alex von Falkenhausen (not to be confused with the contemporaneous general of the same name) led to Stuck driving for his team in Formula Two racing, although with little success.

The fact that she had a Jewish grandfather caused Stuck some problems with the rise of the Nazis, but his personal relationship with Hitler saved him from serious trouble.