He was educated at Achimota School and studied Chemistry at the University of Ghana, Legon, receiving his bachelor's degree with first class honours.
[1][2][3] In October 1970, he was appointed a lecturer in Chemistry at the University of Ghana, Legon and rose through the ranks to become a full Professor.
He was an Alexander von Humboldt Foundation Fellow at the Institute of Pharmacy and Food Chemistry University of Erlangen-Nuremberg in Germany from 1982 to 1984.
[1][2][3] He is a member of the WHO-AFRO African Advisory Committee on Health Research and Development (AACHRD), and was involved in various meetings of AACHRD and WHO-AFRO to study, review and make recommendations on the WHO-CEWG report on Health research and development (R&D), Financing and Coordination.
[1][2][3] Addae-Mensah served as the General Secretary of the Peoples National Party, PNC and Presidential Advisor to Hilla Limann.
[1][2][3] Under the leadership of John Kufuor, Addae-Mensah was awarded the State Honour of Companion of the Order of the Volta (COV) by the Government of Ghana in 2006 for his contributions to education and public service.
[5] In 2016, the University of Ghana, Legon honoured him by naming a road intersection on its campus after him in recognition to his academic contributions and service to the institution.