He was the first chancellor of the Philadelphia bar association and published several influential legal texts including A View of the Constitution of the United States.

He sailed to Europe in 1781 to continue his legal education and attended the Middle Temple in London at the recommendation of William Eden.

[5] He returned to Philadelphia in 1783 and his admission was aided by a hand-written passport from Benjamin Franklin in his role as United States Ambassador to France.

It evolved into Rawle & Henderson which is still in existence and the oldest law firm in the United States.

In 1805, he argued before the United States Supreme Court against the concept that slavery was constitutional.

[1] Their son William Rawle Jr., was also a lawyer and married Mary Anna Tilghman, the granddaughter of Chief Justice Benjamin Chew.

[9] His great-grandfather was Francis Rawle,[23] who authored some early pamphlets printed by Benjamin Franklin before he started his own business.

[9] Rawle's family were Cornish American members of the Religious Society of Friends (known as "Quakers"), originating in the parish of St Juliot, Cornwall.

Their daughter, novelist Mary Cadwalader Rawle, was married to Frederic Rhinelander Jones, the brother of the novelist Edith (Jones) Wharton, and their daughter was renowned landscape architect Beatrix Farrand.