[4] As a nine-year-old boy, Trochowski started his career with Billstedt Horn and then played for SC Concordia and FC St. Pauli, in Hamburg.

On 5 April 2011, Trochowski's agent Roman Grill confirmed that his client would move to Sevilla when his contract expired at the end of the season.

He had been an irregular player for Hamburg during the second half of the season, making just two starts out of 11 possible Bundesliga matches after the winter break.

[6] In his first season with the club, he featured in 35 La Liga games, scoring one goal and providing two assists as Sevilla finished in a disappointing ninth place.

[7] On 15 September 2012, he smashed in a half-volley after only 69 seconds, to hand his side a 1–0 victory over reigning La Liga champions Real Madrid.

[8] In September 2014, Sevilla stated that the club and Trochowski terminated the contract by mutual consent, one year prior then contractually agreed.

His mother sent several letters to the Polish Football Association (PZPN), informing it about her talented son and about his willingness to cap for Poland.

[3] In the German daily Die Welt, however, Trochowski said that, "Even back then, I wanted to play for Germany, because here I enjoyed my schooling and gained my footballing skills.

One year after his move to Hamburg, senior national coach Joachim Löw called him for the first time, and he debuted on 7 October 2006 in a friendly against Georgia at the Ostseestadion in Rostock;[18] he started the game and was replaced by Torsten Frings for the final 14 minutes of the 2–0 victory.