He was originally intended to become a priest; but after his father's death in 1500, his mentor Maciej Drzewiecki convinced Barbara of Rożnowo to abandon this plan.

He travelled extensively across Europe, and was knighted by king Manuel I of Portugal for his services against the Moors in Africa.

In 1536, he became castellan of Kraków and starost of Sandomierz, Stryj, Żydaczów, Dolina, Sandecz, Chmielnów, Lubaczów and Horodło.

[8] In 1545, the Archbishop of Gniezno, Piotr Gamrat, granted hetman Tarnowski a papal brief with indulgences and privileges granted by Pope Paul III in 1535, and in 1547 he was awarded by Emperor Charles V with a diploma of the counts of the Holy Roman Empire - this title was to apply to the hetman and his descendants.

In about 1511, Tarnowski married Barbara Tęczyńska, daughter of Mikołaj Tęczyński, voivode of the Ruthenian Voivodeship.