In 1906, the local Republican committee nominated Coolidge for election to the Massachusetts House of Representatives. He won a close victory over the incumbent Democrat, and reported to Boston for the 1907 session of the Massachusetts General Court. In his freshman term, Coolidge served on minor committees and, although he usually voted with the party, was known as a Progressive Republican, voting in favor of such measures as women's suffrage and the direct election of Senators. On June 2, 1924, Coolidge signed the act granting citizenship to all Native Americans born in the United States. By that time, two-thirds of the people were already citizens, having gained it through marriage, military service (veterans of World War I were granted citizenship in 1919), or the land allotments that had earlier taken place.