He graduated from Harvard University in 1810, studied law, was admitted to the bar and practiced in Charleston and Columbia.
In the 1820s de Saussure served two terms as Intendent, or Mayor, of the City of Columbia. De Saussure was appointed May 10, 1852, and then elected November 29, 1852, as a Democrat to the United States. Senate to fill the vacancy caused by the resignation of R. Barnwell Rhett and served from May 10, 1852, to March 4, 1853. He resumed the practice of law in Columbia, and was a trustee of South Carolina College (now the University of South Carolina) at Columbia for many years.
In December 1860 he was a delegate to South Carolina"s Secession Convention and became a signer of the Ordinance of Secession which led directly to the opening hostilities of the Civil War.
He was a member of the South Carolina House of Representatives in 1846 and a judge of the chancery court in 1847. The descendants of William Ford De Saussure include Arthur Ravenel, Junior. (since 1927), a member of the United States Congress who represented South Carolina from 1987-1995.