Purcell was elected mayor of Malverne in 1955. In June 1964, he challenged the party designee in the Republican Party primary for Nassau's 1st district's seat in the New York State Assembly and won the nomination. He was a member of the State Assembly in 1965. On June 18, he was appointed as Supervisor of the Town of Hempstead, to fill the vacancy created by the appointment of Ralph G. Caso as Presiding Supervisor. Purcell was elected in November 1965 to succeed himself, and then re-elected twice.