Background
He was a son of Rafał Leszczyński (1579–1636).
supporter of Polish Calvinists
He was a son of Rafał Leszczyński (1579–1636).
After finishing his education in 1636, he returned to the Polish-Lithuanian Commonwealth, and after the death of his father he inherited Baranów Sandomierski and nearby lands in Sandomierz Voivodeship, Stary Czartorysk and Nowy Czartorysk in Wołyń Voivodeship, and starostwo dubieńskie. A Calvinist himself, he was tolerant of any religious minorities, and was a major protector of Calvinist churches in Baranów Sandomierski, Romanów and Beresteczko. On 3 March 1641 he became the voivode of the Dorpat Voivodeship, but never became too involved in politics.
He had only one son, Samuel Leszczyński, born in 1637, who inherited his father"s fortune.
He also closed down the Calvinist churches in Baranów Sandomierski and Beresteczko, which he saw as a threat to Leszno.