Born to Mihály Agh and a woman with the surname of Szabo, all three of his sisters had married Unitarian ministers.
In 1734, he was sent to multiple academies throughout Europe, in places such as Amsterdam, Halle, and the universities of Leiden and Rotterdam, and returned home in 1737.
In Kolozsvár, from 1738 onwards, he taught physics, geometry, logic, metaphysics, theology and Hebrew and Greek languages at the local Unitarian college.
In 1754, he became a notary in the Unitarian Church, and after the death of Mihály Lombard de Szentábrahám on 30 March 1758, chose him to be the synod bishop of Kissáros on 21 May.
In order to remedy the situation, Joseph II, the Holy Roman Emperor, presented the church grievances, and each point with respect to the results achieved; He obtained permission to print two volumes written by Mihály's Unitarian Church of Transylvania.