The 24-year-old has signed a four-year contract with die Werkself following Düsseldorf's relegation to the Bundesliga 2.
Kruse arrived at Fortuna in June 2011 from Australian A-League side Melbourne Victory and made eleven appearances for the club in his first season as Düsseldorf returned to the Bundesliga after 15 years. It was in his second year with die Flingeraner, however, that he really caught the eye.
On his top-flight debut, and Fortuna's first game of the season, he assisted both goals in a 2-0 victory at FC Augsburg and scored his first goal in the German top flight against 1899 Hoffenheim on Matchday 11. He hit the target four times in total and provided six assists, but couldn't prevent the club being relegated after defeat to Hannover 96 on the season's final day.
He made his international debut in January 2011 and has managed 21 caps so far, scoring twice.