A youth product of
First Vienna FC, Demir joined the youth academy of
Rapid Wien in 2013. On 20 May 2022, he signed his first professional contract with
Rapid Wien until 2024, and was promoted to their reserves in the
2. Liga. On 22 May 2024, he extended his contract with Rapid Wien until 2026. On 5 September 2024, he was loaned out
TSV Hartberg in the
Austrian Football Bundesliga for the 2024–25 season. He made his senior and professional debut with Hartberg in a 2–2 Austrian Bundesliga tie with
Austria Klagenfurt on 21 September 2024. ==International career==