Chrzanowski was born and died in Warsaw, Poland. During World War II he was a member of the Polish anti-Nazi resistance organization, the Home Army.[2] He finished a law degree at a secret underground university in 1945.[2] During the second half of the 1970s he became associated with the opposition to the communist government in Poland.[2] He helped to draft the statutes establishing the Solidarity trade union and later was the lawyer which guided the legal registration process of the organization.[2] In 1989 he founded the Christian National Union (ZChN), party he chaired to 1994.