Egan was elected to the Legislative Council on 1 April 1854, representing the Pastoral District of Maneroo. In April 1856 he was elected at the first election to the Legislative Assembly, representing Maneroo, which was renamed Monaro in 1858. From 1859 to 1869 he represented Eden and from 1870 to his death he represented Monaro. From 27 October 1868 until his death he was the Postmaster-General of New South Wales.