Descended from a branch of the Marinid dynasty, he entered the Nasrid service under Muhammad III after a failed rebellion against Sultan Abu Yaqub Yusuf in his native Morocco. He was appointed to lead the Volunteers of the Faith in the western city of Málaga. When Muhammad III came into conflict with Abu Yaqub Yusuf over Ceuta, Uthman allied himself with Granada, conquered a part of Morocco and declared himself Sultan.