He was nominated to the New South Wales Legislative Council in 1860, in 1869 was elected a member of the New South Wales Legislative Assembly for Glebe, and from December 1873 to February 1875 was minister for justice and public instruction in the first Henry Parkes ministry.
He was nominated to the New South Wales Legislative Council in 1860 and remained there until May 1861. In 1869 Allen was elected a member of the New South Wales Legislative Assembly for Glebe, and from December 1873 to February 1875 was minister for justice and public instruction in the first Henry Parkes ministry.