Painter. Born in Edinburgh, the elder brother of John Runciman (1744-68), with whom he worked closely. Runciman taught in Edinburgh, one of his pupils being the noted Neo-Classical painter Jacob More (1740-93). The brothers travelled to Italy together in 1767, under patronage of Sir James Clerk of Penicuik, but unfortunately John died there the following year.
Runciman became one of Scotland's foremost decorative painters and his most notable work was inside Penicuik House (1772), where he painted scenes from Scottish history. Sadly this work was lost in the fire which destroyed the house, although the artist's sketches remain. He also painted panels at the Church of St. Patrick in Edinburgh's Cowgate (1774), although his mural The Ascension was later painted over and is subject to restoration.