Smirke was called to the bar at the Middle Temple on 12 November 1824, went on the western circuit, and attended the Hampshire sessions.
By letters patent under the great seal of England he was constituted on 2 July 1853 vice-warden of the stannaries of Cornwall and Devon, which post he held until 29 September 1870.
As a student, Smirke had a predilection for the investigation and elucidation of charters, and for the history of mining in Cornwall.
He died at 18 Thurloe Square, South Kensington, on 4 March 1875, and is buried at Kensal Green Cemetery, London.
[2] He married at Kensington, on 11 September 1838, Harriet Amelia, youngest daughter of Thomas Neill of Turnham Green.