He was the son of Lew Sapieha. Jan studied abroad. He was a friend and supporter of prince and later king Władysław IV Vasa and served as a deputy to many Sejms. Sapieha took part in the Polish-Swedish wars, but gained the reputation of a weak tactician and suffered several defeats. Near the end of his life he had mental health problems, but his friend king Władysław IV allowed him to remain at the royal court until his death.