Engineer. Smith was a lamp-maker who became the first Engineer to the Northern Lighthouse Board when it was created in 1786. Robert Stevenson, the father of the famed 'Lighthouse Stevenson' dynasty became his apprentice in 1791, and his step-son in 1792. In 1796 Smith gave control of the lighthouse part of his business to Stevenson, retiring from the Northern Lighthouse Board the following year again in Stevenson's favour. Stevenson married Smith's daughter, Jane, in 1799.
Smith was responsible for the design of ten lighthouses; the first at Kinnaird Head in Aberdeenshire was built in 1787 and is now the Museum of Scottish Lighthouses. The others were on the Mull of Kintyre (1788), North Ronaldsay (1789), Eilean Glas on Scalpay (1789), Pladda, off Arran (1790), Little Cumbrae (1793), Muckle Skerry in the Pentland Firth (1794), Cloch Point (1797), Inchkeith (1804) and Start Point (1806).