He married Borbála Várady (d. 1661) in 1637, they had two sons, including Miklós, future Chancellor of Transylvania, and two daughters.
He served as Captain General of Udvarhelyszék between June 1660 and 1667 (except the short period of Kemény's rule).
He founded the Calvinist College in Székelyudvarhely (today: Odorheiu Secuiesc, Romania).
In 1676, he accused of having participated in the conspiracy of Pál Béldi, as a result he was deprived from his positions.
The Chancellor rights were exercised by his distant relative Farkas Bethlen until the next year when János regained his office.