1974 ahyɛaseɛ no Mensah yɛɛ abanmu ne ankorɛankorɛ adwuma wɔ Ghana ne aburokyire. National Redemption Council de no too afiase firi 1975 kɔsi 1978. Berɛ ɛ na yɛabra no amanyɔ mpo no ɔdii Popular Front Party amanyɔsɛm mu akoten wɔ 1979 mu. Ɔyɛɛ Sunyani District Council a ɛwɔ Brong-Ahafo Region no titenanin (1979–1981), ɛna Banka Farms adwumawura. Wɔpam no kɔɔ Englesi 1983 no ɔkɔyɛɛ ɔhwɛsonin maa ekuo a na ɔne PNDC redi asie. Na ɔsan nso ka African Advisory Council of the African Development Bank ho firi 1993 kɔsi 1997. Ɔpɛnimaa 1996, Mensah peree Sunyani East constituency marahyɛbadwa akonnwa no maa New Patriotic Party, ma ɔdii nkonim. Afe 2000 no nso wɔsan to aba yii no. Na ɔyɛɛ Minority Leader wɔ mmarahyɛ badwamu firi 1997-2000 ansa na Ɔmanpanin Kuffuor aban reba so. Ɛno akyi no na ɔyɛɛ Minister and Leader of Government Business firi 2001 kɔsi 2003; Minister for Public Sector Reform and National Institutional Renewal Programme firi 2003 kɔsi 2005 ɛna Senior Minister firi 2005 kɔsi 2006 a ne nyinaa wɔ Kuffuor aban no mu.