He is generally considered to be one of the foremost designers of German-style board games.

Moon has worked as a game designer for Avalon Hill, Parker Brothers, and Ravensburger F.X.

[1] But his first game that got him attention was Airlines, published by the German company Abacus in 1990.

[1] He started his own publishing company, White Wind in 1990 and ran it until 1997.

[1] Moon has won the Spiel des Jahres award twice, for Elfenland in 1998 and for Ticket to Ride in 2004; Ticket to Ride has won almost two dozen other awards worldwide.