On 26 July 2011, he signed a contract extension to keep him at the club until June 2016. On 24 September 2011, he scored his first goal for his new German club, a last-minute volley to win the match away to Mainz 05 2–1. In the 2012–13 season for Dortmund, Piszczek appeared in 11 out of 12 matches of Dortmund's road to the UEFA Champions League Final in 2013.
On July 26, 2011, he signed a contract extension until June 2016. On September 24, 2011, he scored his first goal for the new German club, which was a last-minute volley that won the match against Mainz 05 with a score of 2–1. In the 2012-13 season at Dortmund, Piszczek played in all but two matches, helping Dortmund reach the UEFA Champions League Final.