From 1768 to 1772 one of the leaders of the Bar Confederation, considered by some to be the first Polish uprising. It was formed by Polish nobility who opposed Russian intervention into Polish internal politics; Krasiński also criticized the Holy See for its silence on the matter of arrest of several Polish nobles during that time, including two bishops (Kajetan Ignaty Sołtyk and Józef Andrzej Załuski, by the Russians. In the Bar Confederation he became their most important diplomat, responsible for many negotiations and their relations with foreign powers. In October 1768 he went to Paris where he was received by Louis XV of France who promised support for the confederates. In 1769 he advocated the assassination of King Poniatowski, later that year he became the head of the confederate's government in Biała. In 1770 he went to Dresden to gain support from the Holy Roman Empire; later that year he met Joseph II, Holy Roman Emperor and received an offer of help from him. Also he did not support the declaration that King Poniatowski is not the legitimate king of Poland, he nonetheless supported Frederick Augustus I of Saxony as a counter-candidate. He was likely one of the supporters or even the ring-leader of the plan to kidnap Poniatowski, eventually carried by Casimir Pulaski in 1771. That plan nonetheless backfired, as Poniatowski not only escaped but this action caused much controversy in Europe and resulted in loss of much international support for the confederates. Eventually in 1772 he began negotiations with the King about surrender of the confederates; later that year he himself was kidnapped by the Cossacks and temporarily imprisoned in Warsaw. He was nonetheless set free after he pledged loyalty to the king and regained his posts in the Polish–Lithuanian Commonwealth.