He owed his successful career partly to the patronage of the distinguished Bulkeley family of north Wales, and later to the Earl of Macclesfield.
As a mathematician, his main claim to fame is that he proposed the use of the symbol π (the Greek letter pi) to represent the ratio of the circumference of a circle to its diameter. He became a close friend of Sir Isaac Newton and Sir Edmund Halley. In 1712, he became a Fellow of the Royal Society, and was later its Vice-President.
His son, also named William Jones, was a famous philologist who discovered the Indo-European language group.