Akpınar started his career in the BC Hamburg youth ranks.[1] At the age of 16, he made his professional debut with SC Rist Wedel in the ProB, the third tier of German basketball, earning Eurobasket.com All-German ProB Rookie of the Year honors following the 2011–12 season.[2] At the same time, he excelled at the youth level playing for Piraten Hamburg and was named JBBL (under-16 Bundesliga) Player of the Year in 2011[3] as well as NBBL (under-19 Bundesliga) Rookie of the Year the following season.[4]
On June 7, 2017, he signed with ratiopharm Ulm.[7] In the 2017–18 season, he was invited for the BBL All-Star Game for the first time in his career. In 2019, Akpinar played in his second All-Star Game and was MVP of the match.[8]
Akpınar has represented the German Junior National Teams on many occasions. In August 2010, he played in the North Sea Development Basketball Cup, guiding the German under-15 squad to a second-place finish.[15]
He was with the Germany U16 National Team, competing in the 2011 under-16 European Championships,[16] and was selected to play for Germany's U18 team at the 2012 Albert-Schweitzer-Tournament[17] as well as at the 2012[18] and 2013[19] under-18 European Championships. In 2014[20] and 2015,[21] he played for his country in the under-20 European Championships. In the summer of 2017, he was capped for the first time for Germany's men's national team.[22]