Joseph Gwilt (1784-1863), son of George Gwilt (1746-1807) followed in his father's footsteps as an architect joining his practise in 1799. In 1801 he went to the Royal Academy where he was awarded a silver medal for his drawing of the tower and steeple of St. Dunstan's-in-the-East. His best known works are Lea Church, near Lewisham (now destroyed), the approaches to Southwark Bridge, Marktree Castle, Co. Sligo and his largest work St. Thomas, Charlton, Southwick and the additions he made to the Grocers' Company.
Gwilt distingiuished himself as a writer on architectural subjects including "Treatise on the Equilibrium of Arches, in which the Theory is demonstrated upon Mathematical Principles" 1811 and "The Encyclopedia of Architecture " 1842. He travelled throughout Europe and the British Isles and recorded each trip with narrative, sketches and souvenirs which were later bound into volumes. The R.I.B.A., London has the "Slight Memoir of Joseph Gwilt" by his son Sebastian Gwilt, compiled 1882, in which a photograph of Joseph Gwilt by Thomas F.A. Byles compares favourably with the present miniature.

It has been suggested that Gwilt is holding one of his drawings for the R.A. diploma which was never executed