William Smith was born in 1777 in New Haven, CT. He came to Rodman in 1802 and then to Watertown in 1805 and entered into mercantile business with John Paddock in Watertown. By 1807, they were joined by John's brother, Loveland. In that same year, he designed a courthouse for the recently created Jefferson County (It stood near the present site of Old Jail Antiques). When the Village Council declined Henry Coffeen's offer to make upper Massey Street- then Madison Square- into a public park, Coffeen built a massive building in front blocking its view from the village. The village repayed Coffeen's act of defiance by moving the courthouse to Arsenal Street.
In 1806 and 1807, he was appointed commissioner of navigation on the Black River. During the War of 1812, Smith designed a cantonment for the sailors and marines stationed at Sackets Harbor, a structure that came to be known as Smith Cantonment. He also commanded a militia company during the Battle of Sackets Harbor. At the war's conclusion, he drew plans for the shiphouses at Sackets and Storrs Harbors to cover the unfinished ships under construction there. With that success, he was asked to design a similar but more permanent structure at Madison Barracks, built on the site of Fort Pike after the war ended.
In 1814, Smith was appointed superintendent of the Jefferson Cotton and Woolen Manufacturing Company. He designed and superintended construction of the large factory on Cowan's (now Beebe's) Island. It subsequently burned in 1833.
In 1828, William Smith was appointed a receiver in the court of chancery on the matter of John LaFarge v. Philip Schuyler. In 1832 he was appointed agent and attorney for a class action suit against the government by persons owed for services and materials used in the construction of Madison Barracks since 1816. In 1833, he joined Orville Hungerford in lobbying for a railroad connection to Watertown. In 1848, he was among those on the Board of Directors of the Rome, Watertown and Ogdensburg Railroad Company.
He died Nov. 24, 1858 in Watertown.