Osei-Kwaku was a member of the New Patriotic Party, he served as the member of parliament for the Asokwa West constituency from 7 January 1997 to 6 January 2005. During the 1996 Ghanaian general election, he polled 42,734 votes which accounted for 52.7% of the total votes cast, and during the 2000 Ghanaian general election, he polled 48,738 votes which accounted for 74.5% of the total votes cast. During the Kufuor administration, he was appointed deputy Minister for Presidential Affairs and later Minister of Youth and Sports. During his tenure of office as the Minister of Youth and Sports, he helped initiate the bid for Ghana to host the CAN 2008 tournament. He also aided in the rehabilitation of Ghana's then major stadia, the Accra Sports Stadium and the Kumasi Sports Stadium (now Baba Yara Stadium).