Nkansah's political career begun when he was nominated member of the constituent assembly for two constituencies Asunafo and Asutifi in a tripartite competition. Nkansah was sworn into office as a member of parliament on 1 October 1969, following his election during the 1969 Ghanaianparliamentarygeneral election. He served as a member of parliament for the Asunafo Constituency on the ticket of the Progress Party from 1969 to 1972 when the Busia government was overthrown. In 1979, he was a member of the Legislative Assembly but was later expelled by the Privilege Committee of the assembly for being absent for five consecutive days without permission. That same year, he was elected member of parliament for the Asunafo Constituency on the ticket of the Popular Front Party. He served in this capacity from 1979 until the 31 December 1981 when the Limann government was overthrown.