Hugo Treffner was born in a family of local parish clerk in the village of Kanepi.
He was director of Treffner Gymnasium for the rest of his life while he also worked as religion teacher in other schools.
Treffner was described by his contemporaries as a skilled politician who managed to get along with the Russian authorities very well to benefit his school.
Treffner actively took part in the national movement, in which he sided himself with Carl Robert Jakobson.
Hugo Treffner inspired A. H. Tammsaare to create the character of "Mister Maurus" in his second book of Truth and Justice.