From 1786 to 1792 he worked for the Polish Commission of the Treasury and was responsible for supervising Jewish affairs in the country. During this time and afterwards, he worked for the emancipation of Jews in Poland. Exemption from the poll-tax was granted in 1775 to those who would apply themselves to agriculture, and by 1787, owing to Czacki's efforts while in the treasury (see his report of 1787 on the Ruthenian and Ukrainian provinces), he had the satisfaction of seeing a few scores of families enjoying that privilege. Furthermore, he co-wrote the Constitution of 3 May 1791, and founded the Towarzystwo Przyjaciół Nauk ("Society of Friends of Science").