William Sublette was born in Stanford, Kentucky, on 21st September, 1799. His family moved to Missouri in 1817 and lived in St. Charles.
On 13th February, 1822, William Ashley placed an advertisement in the Missouri Gazette and Public Adviser where he called for 100 enterprising men to "ascend the river Missouri" to take part in the fur collecting business. Those who agreed to join the party included Sublette, Jim Beckwourth, Tom Fitzpatrick, David Jackson, Hugh Glass, James Bridger and Jedediah Smith.
Ashley's company was the first to depend primarily upon trapping the beaver rather than buying them from Native Americans. Ashley did not pay the trappers a fixed wage. Instead, in return for transporting them to the Rocky Mountains, he took a share in the furs they obtained.
On 30th May, 1823, Ashley and his party of 70 men were attacked by 600 Arikaras. Twelve of Ashley's men were killed and the rest were forced to retreat. Jedediah Smith volunteered to contact Andrew Henry and bring back reinforcements. A message was sent back to St Louis and Colonel Henry Leavenworth of the U.S. Sixth Infantry and later 200 soldiers and 700 Sioux allies attacked the Arikara villages.
Sublette remained a mountain man for several years. In 1824 Sublette went with Jedediah Smith to the far northwest. Two years later he went into partnership with Smith and David Jackson when they purchased the fur business of William Ashley.
Sublette became briefly involved in the Sante Fe trade but abandoned the idea after the death of Jedediah Smith. He returned to the Rocky Mountains and was wounded during the battle at Pierre's Hole in July 1832. Sublette established a new company with Robert Campbell but later sold it to the American Fur Company.
Sublette now moved to St Louis where he became involved in business and politics. He also invested in a stock farm.
William Sublette died at Pittsburgh on 23rd July, 1845.