Farkas was the son of Ferenc Bethlen, Ispán (Count; comes) of Fehér County, Marshal of George II Rákóczi, and Kata Kemény de Magyargyerőmonostor.
After that his educator was Pál Keresztúri in the court of George II Rákóczi.
He also functioned as Ispán of Fehér County from 1661 until his death with a short break.
After the death of Rákóczi he was a supporter of princes John Kemény and Michael I Apafi.
He served as acting Chancellor between 1676 and 1677 when his distant relative János Bethlen was charged with conspiracy.