Ryan van den Akker and Herman van Veen did not only do the voices for the Dutch episodes but also for the German ones.
The show's creator and therefore Alfred's literary father Herman van Veen voiced three of its characters. One of them was Johan Kwak, Alfred's in-universe father.
Dolf, Alfred's nemesis, speaks Dutch with a German accent, as does his father in the pilot. Later, when he takes over Alfred's kingdom as a dictator. Although his uniform is reminiscent of Napoleon Bonaparte, his name, rise to power and his moustache are blatant references to Adolf Hitler.
According to Herman van Veen, the show was partly conceived out of his personal guilt for accidentally running over a duck with his car.
Alfred's full name is Alfred Jodocus Kwak.