His family moved to Karadeniz Ereğli, Zonguldak when Demir was five years old. He has four brothers: two older and two younger twins. Demir played for his school team before Karadeniz Ereğli Belediyespor signed him to a youth contract in 2002.
When asked what his goals were as a football player, Demir replied "I didn"t have any goals when I started playing football.
lieutenant was just a game for me, but then I was signed to Karadeniz Ereğli Belediyespor. I wanted a better life for my family." Demir"s favorite football player is Fatih Tekke, a fellow striker from Trabzon.
Sedat Özden, a former professional football player who played for, spotted Demir at a youth tournament in Ankara. He became interested in bringing Demir to Bursa after he helped lead Karadeniz Ereğli Belediyespor to the championship.
Bayram Altıntaş, Demir"s coach at Karadeniz Ereğli Belediyespor, offered Demir to
The club signed Demir to a youth contract at age 12. Due to his small stature and differences between his small hometown and the more modern, bustling city of Bursa, Demir quickly became homesick. After spending one month with, he packed his bags and returned home.
Although he was highly coveted by the coaches in Bursa, Demir was reluctant to return.
lieutenant was then that his father told him "go there (Bursa) and finish school. If you don"t want to become a football player, then at least finish school and come home." Demir described his first season as a bad one.
He said his teammates couldn"t believe he was given a chance to play due to his bad form. However, his coach Yılmaz Burul believed in Demir"s abilities and pushed him forward.
Demir was named captain the following season.
He has scored 17 goals in 27 A2 matches. Demir joined in 2005 and signed a professional contract in 2007. He made his first appearance in the Süper Lig in the final game of the 2008-2009 season, coming off the bench in the 86th minute against.
Demir regularly trains with the senior squad, but has not been able to play many games due to injuries.
Chelsea and West Ham courted Demir and made offers after he scored two goals against Russia in a youth national team match. turned both offers down, stating that it was too soon for Demir to leave the club He has stated that he does not want to play for an Istanbul club such as Fenerbahçe or Galatasaray, but move abroad instead.
After refusing to sign a new deal with his current club, he was sent to in January 2011. In the last day of the transfer period he accepted to sign a contract with for four and a half years.
Demir led the Turkey U-17 squad to the quarter finals of the 2009 Fédération internationale de football association U-17 World Cup in Nigeria, where the team lost 5–3 on penalties to Colombia.
He scored three goals and notched one assist during his five games at the tournament, good enough for joint third place for top scorer. On 10 October 2014, Demir played his first national match for Turkey against the Czechoslovakian Republic in Istanbul, replacing Olcay Şahan after 66 minutes of a 2–1 defeat.