[1][2] The son of sculptor Edward Smyth (1749–1812),[3] John Smyth was trained at the Dublin Society's school, and worked with his father at Montgomery Street (now Foley Street) in Dublin.
[4][5] One of his first public works was a monument to John Ball in St Patrick's Cathedral, Dublin.
[6] He assisted his father, Edward, with a number of sculptures at Parliament House (now Bank of Ireland), the King's Inns, and with decorative plaster and stonework at the Chapel Royal of Dublin Castle.
[7] He also sculpted the statues of Mercury, Fidelity, and Hibernia for the pediment of the General Post Office, Dublin (c.1814).
[9] In 1818, Smyth was commissioned to produce a bust of Charles Whitworth, 1st Earl Whitworth, then Lord Lieutenant of Ireland, which was displayed at the Society of Artists in 1819 alongside a bust of his wife Arabella by Thomas Kirk.