Born in Makhachkala, Russia, Mustafaev moved to Poland at the age of six.
[1] Mustafaev started his career with Polish side Stal Rzeszów.
In July 2023, shortly after being promoted to Legia Warsaw's senior team and being registered to play in Ekstraklasa,[2] Mustafaev suffered an ACL tear.
[3] On 21 February 2025, he moved to the reserve side of fellow Ekstraklasa club Cracovia on a half-year deal.
[5] He is the brother of Russian mixed martial arts fighter Azamat Mustafaev.