Apprenticed to a stonemason after being left an orphan, he later went to Birmingham where his elder brother William was an architect (and who later moved to Canada to continue his career).

He was noticed by Charles Barry who immediately employed John Thomas as a stone and wood carver on Birmingham Grammar School (now demolished), his first collaboration with Augustus Welby Northmore Pugin.

[1] Thomas's work 'Charity' was shown at the Great Exhibition of 1851, and then adapted to form a memorial in Christ Church, Chalford, to his brother Richard who died in 1852.

His final work was the colossal statue of William Shakespeare displayed at the 1862 International Exhibition.

A dispute over its placement hastened his death in April 1862, and he was buried in Kensal Green Cemetery, London.