Born in Dundee on 25 March 1868, the son of a plasterer, Clark's family moved to London when he was still young.
In 1913 Clark joined with Harry Fenn, a surveyor, founding a company at Loughborough Junction to specialise in ornamental fibrous plasterwork and Plaster of Paris work.
The business was a rapid success with commissions from the new cinemas and major theatres who competed against each other through the splendour of their interior decoration.
The company soon moved to larger premises at Clapham Old Town where they were able to prefabricate much of their work off-site.
This allowed them to take the mouldings ready-prepared for installation to a theatre or cinema, minimising the disruption to performances and rehearsals.