William Small, the son of a Presbyterian minister, was born in Carmyllie in Scotland. He attended Dundee Grammar School, and Marischal College, Aberdeen where he received an MA. In 1758 he was appointed Professor of Natural Philosophy at the College of William and Mary in Williamsburg, Virginia, which is where he met and taught Thomas Jefferson.
In 1764 Small returned to Britain, with a letter of introduction to Matthew Boulton from Benjamin Franklin. Through this connection Small was elected to the Lunar Society.
In 1765 he received his MD and established a medical practice in Birmingham. Small was Boulton’s physician and he became a close friend of Erasmus Darwin, Thomas Day, James Keir and James Watt.
He helped to bring the Theatre Royal to Birmingham in 1774 and was involved in planning and building Birmingham General Hospital.
Small died in Birmingham and is buried in the city’s St. Philip’s churchyard.