He joined Werder Bremen in 1995 at the age of twelve and stepped up to the reserve side, playing in the Regionalliga in 2001–02. He made his Bundesliga debut on 15 February 2003 as a substitute against 1. FC Nuremberg. When Ümit Davala was injured, Schulz stepped in and made the left back position his own.
Although Schulz had previously stated that he did not want to leave Bremen, he moved to Hannover 96 on 30 August 2007.
He has four caps for the Germany national team, making his international debut on 16 December 2004 in a 3–0 friendly win over Japan.