Gustafsson was granted the title of International Master in 1999 and that of Grandmaster in 2003. He is one of the strongest German players; he finished second in the 2004 and 2005 German championships, and won the German championship of blitz chess in 2001. He was nominated to the German national chess team in 2002, represented his nation at the 36th, 37th, 38th and 40th Chess Olympiad, and was part of the German team that won the 2011 European Team Chess Championship.