He was also a member of the Swedish four-estates parliament, elected three times as representative of the clergy in the northern and western parts of Finland. In his first parliamentary session, 1765–1766, he was very successful as a member of the subcommittee that wrote Sweden's famous Constitutional Law of the Freedom of Printing, Tryckfrihetsförordningen, of 1766. In this law Chydenius combined freedom of the press, and abolishment of the political censorship, with free access for the citizens to most government documents. Chydenius liberal system, where transparency reinforces press freedom, and the right for everyone to print the public document reinforces transparency, has been a fundamental constitutional principle in Sweden ever since, except for the years of royal autocracy 1772–1809. Chydenius model for press freedom and freedom of information was reestablished and strengthened in the Swedish Constitution 1809. It is now the foundation of the present Tryckfrihetsförordningen of 1949, which is one of the fundamental laws of Sweden.