In July 1951 he was elected to the Knesset, but resigned six weeks later. He returned to the Knesset following the 1959 elections, and shortly after became a Liberal Party MK when it was formed by a merger of the Progressive Party and the General Zionists. After retaining his seat in the 1961 elections, Kol was part of a group of largely ex-Progressive Party members which broke away from the Liberal Party to form the Independent Liberals in protest at its impending merger with Menachem Begin's Herut.