Lighthouse Engineer. Born in Edinburgh and educated at the High School in the city, he continued in his father Robert Stevenson's (1772 - 1850) foot-steps as Engineer to the Board of Northern Lighthouses (1843 - 53). In 1844, he was responsible for the remarkable Skerryvore Lighthouse, on the west coast off Tiree in the Inner Hebrides. His other lighthouses were: Little Ross (1843), Covesea Skerries (1846), Chanonry Point (1846), Cromarty (1846), Cairn Point (Loch Ryan) (1847), Noss Head (1849), Ardnamurchan (1849), Sanda (1850), Heston Island (1850), Hoy (1851) and Arnish Point (1853).
His brothers David (1815-86) and Thomas (1818-87) were also part of the Lighthouse Stevenson dynasty. Alan was the uncle of author Robert Louis Stevenson (1850-94).