Rafał started his political career in the Sejmik of the Sandomierz Voivodeship. He was an opponent of king Sigismund III Vasa, but he never rose up in open rebellion like the participants in the Zebrzydowski Rebellion. He was Protestant, and was a defender of Protestant rights and religious tolerance in the Polish–Lithuanian Commonwealth, dedicating most of his political influence to matters of religion. He provided shelter for Czech Brethren and refugees from Silesia during the Thirty Years' War. He sponsored many new Protestant churches and schools, and developed existing ones, like the school in Leszno, under Czech pedagogue Jan Amos Komeński. He was called the "Pope of Calvinists in Poland." In foreign politics, he supported cooperation with both Catholic France and Protestant countries like Sweden.
He corresponded with Gabor Bethlen of Transylvania and George William, Elector of Brandenburg. George William of Brandenburg gave him a yearly donation of 3000 zloty, in exchange for his support for Protestant cause. After 1629 he also corresponded with Axel Oxenstierna, the Swedish chancellor. He was a strong supporter of the marriage between Władysław IV Waza and a Protestant (Calvinist) princess. He took part in the 1635 negotiations with Sweden, where he worked with the French ambassador, count Claude d'Avaux. He advised the king against hostilities with Sweden, and after the peace of 1635, he wanted to direct Polish foreign policy towards Silesia.
During his life he gathered substantial wealth: 17 towns and over 100 villages in Wielkopolska, Baranów and nearby lands in Sandomierz Voivodeship, Włodawa in Polesia, Woronczyn, Romanów and Beresteczko on Wołyń and Ruś. In 1612 founded the Wieniawa near Lublin.