Accra Hearts of Oak SC
Born in Accra, Osei began his career in 2001 with regional club Echomog, and moved to Suhum Maxbees of the Poly Tank Division One League a year later. He played for his third team in as many years in 2003 after transferring to Accra Hearts of Oak SC, before moving to Turkey to play for Akçaabat Sebatspor (then in the top flight), also in that year.