Sears was a Member of the Massachusetts House of Representatives from 1935 to 1937 and the Massachusetts Senate from 1939 to 1943 and again from 1947 to 1949. Sears was Massachusetts Republican State Chair from 1949 to 1950 and was delegate to 1948 and 1952 Republican National Conventions from Massachusetts. He stepped down as chairman of the State Committee after his attempt to liberalize the party failed to gain traction with other party leaders.