Demir joined the SPD in 2010. He worked in the parliamentary office of SPD member of parliament
Karamba Diaby from
Halle (Saale). In a member poll in the run-up to the
2021 Bundestag election, Demir won the direct candidacy in the Neukölln constituency with 51.95% to 45.18% against fellow candidate
Tim Renner. Although the latter had been considered the favourite of Berlin SPD lead candidate
Franziska Giffey and Neukölln district mayor Martin Hikel. He thus entered the Bundestag as Neukölln's representative. Since 8 July 2022, he has also been a member of the 1st Committee of Inquiry of the 20th parliamentary term of the German Bundestag. Demir is co-chair of the state working group on migration and diversity in Berlin. He is a member of the state executive committee of the SPD Berlin. Within his parliamentary group, Demir belongs to the
Parliamentary Left, a left-wing movement. In the
negotiations to form a
Grand Coalition under the leadership of
Friedrich Merz's Christian Democrats (
CDU together with the Bavarian
CSU) and the SPD following the
2025 German elections, Demir was part of the SPD delegation in the working group on cultural affairs and media, led by
Christiane Schenderlein,
Volker Ullrich and
Carsten Brosda. ==Other activities==