William Cookworthy was born in 1705, the son of a Quaker weaver from Kingsbridge in Devon. When he was 14 years old, William was taken on as an apprentice by Silvanus Bevan, a Quaker chemist and druggist based in London. William, unable to afford the coach fare from Devon to London, made the 200 mile journey on foot.

In addition to his training in dispensing, Cookworthy also learned Latin, Greek and French, and some metallurgy.

In 1726, Bevan offered him a position in a new wholesale pharmacy business in Plymouth. By 1735, they were partners. His late wife's brother joined Cookworthy to form "Cookworthy and Company". It was about this time that William began to spend time on chemistry and metallurgy experiments.

The business flourished, supplying merchant ships in the busy port. He even came into conflict with the Society of Apothecaries in London in 1755 when he ignored the monopoly that Queen Anne had granted to them in 1702 to supply Naval ships. However, he is said to have entertained Captain Cook and Joseph Banks before they sailed in Endeavour to Otaheite, in the Pacific Ocean, in 1769.

Cookworthy's most famous achievement was his work at the pioneering stages of the porcelain industry in England. It seems that he entered the subject area by accident, having read a description of Chinese porcelain manufacture written by a Jesuit missionary in the 1740s.

He described that he was able to investigate further when three men visited him from Virginia with samples of Virginian clay and porcelain in 1745.

The visitors were keen to interest Cookworthy in importing the Virginian clay to make porcelain in England, as was already happening in Bristol. However, to make the Chinese hard paste porcelain, both kaolin (China clay) and a harder variety called petuntse (China stone) were needed.

Cookworthy decided to look for these minerals in England, and he found them locally in Cornwall. They were known as Moorstone or Growan, and Growan clay. Cookworthy began to experiment with these ingredients. However, it took him until 1768 to file a patent specification, and be granted Patent number 898 for "Making porcelain from Moorstone, Growan and Growan clay."

He set up the Plymouth China Works with Thomas Pitt, Lord Camelford, on whose estate he had found the minerals and produced the first English hard paste porcelain. They primarily made decorated tea services, jugs and vases. However, the business was not making a profit in Plymouth, and it amalgamated with a pottery in Bristol. Cookworthy made his cousin, Richard Champion, his manager of "William Cookworthy and Company." In 1774, Cookworthy sold his interest in the business and patent to Champion. Champion continued to buy the ingredients for the porcelain from Camelford, and paid a royalty to Cookworthy. Cookworthy and Bevan's apothecary shop, established in 1735, continued as a pharmacy premise until 1974 when the last proprietor retired.