Painter, best known for his military art. Born at Laurieston (Falkirk), Gibb trained in Edinburgh at the Board of Manufactures and the Royal Scottish Academy. He gained a reputation as a painter of portraits and landscapes, but was particularly noted for his romantic and historical military works. His most famous work is The Thin Red Line (1881), which illustrates an action by the Sutherland Highlanders in the Battle of Balaklava (1854), while other works include Alma : Forward the 42nd (1888) which is held by the Glasgow Museums and Art Galleries, Comrades: the 42nd Highlanders (1894) in the Black Watch Regimental Museum, Closing the Gates at Hougoumont, 1815 (1893), held by the National War Museum of Scotland, together with Napoleon's Surrender (1924) and Backs to the Wall, 1918 (1929).
Gibb held the position of Keeper of the National Gallery of Scotland (1895 - 1907), and served as Limner to the King from 1908 until his death. He died at his home in Bruntsfield Crescent in Edinburgh, and was given the honour of a full military funeral prior to burial at Warriston Cemetery.