[7] Leven's first professional stint came after signing with the Perth Wildcats of the Australian National Basketball League in 2006.
[10] However, on 1 February 2008, he left Iceland before debuting[9] and joined the Newcastle Eagles of the British Basketball League (BBL).
[14] Leven initially signed with Greek club Kavala/Panorama for the 2008–09 season, but never debuted for them and left due to their financial problems.
[14] In the 2009–10 season, Leven played for the Tees Valley Mohawks of the English Basketball League (EBL).
[14] Leven initially signed with Greek club SEFA Arkadikos for the 2010–11 season, but never debuted for them and left due to their financial problems.
He was accused of falsifying his PhD, supposedly from Columbia University for applied artificial intelligence.
Leven had also claimed to be a member of a United Nations association for artificial intelligence, to which this also reportedly was not true.