Thread manufacturer. Born at Dykebar, on the edge of Paisley (Renfrewshire), Clark was the son of a farmer who died when he was a child. Unable to work the farm, his mother moved into the town. Clark worked in the textile industry. He is credited with the invention of the wooden spool or bobbin, which was more efficiently used by the weaving machines coming into use at this time. Previously thread was sold in hanks or skeins. Clark produced his thread on these spools and charged his customers a deposit for them which was refunded when the empty spool was returned. He and his brother Patrick went on to develop a smooth cotton thread which could be used in place of silk, the import of which into Britain was banned by Napoleon.
They had a factory at Seedhill which became the Anchor Mills. Their company expanded to the USA in 1864, opening a mill in New Jersey. Eventually their company, J. & J. Clark, merged with their fierce competitors J. & P. Coats to form Coats and Clark.
Clark died in Paisley. His great great grandson was academic and broadcaster Lord Clark (1903-83).