He was born in
Edinburgh, and studied at the Foulis Academy,
Glasgow. From 1750 to 1762 he was apprenticed to the landscape painter Robert Norie, later becoming a partner in the Norie family firm. He also worked as a stage painter for the Theatre Royal in Edinburgh. In 1767, with financial support from Robert Alexander of Edinburgh, he went to Rome, where he spent five years. His brother John accompanied him, but died in
Naples in the winter of 1768–69. During Runciman's stay in Italy he became acquainted with other artists such as
James Barry,
Henry Fuseli and the sculptor
Johan Tobias Sergel. Runciman's earliest efforts had been in landscape; he now turned to historical and imaginative subjects, exhibiting his
Nausicaa at Play with her Maidens in 1767 at the Free Society of British Artists, Edinburgh. On his return from Italy after a brief time in London, where in 1772 he exhibited in the
Royal Academy, he settled in Edinburgh, and was appointed master of the
Trustees' Academy. He was patronised by Sir
James Clerk, decorating the hall of his
Penicuik House with a series of subjects from
Ossian which took inspiration from
Gavin Hamilton's
Iliad pictures, and an adjacent staircase with four scenes from the life of
Saint Margaret. He was a member of the Edinburgh
Cape Club. He enjoyed a strong reputation as a landscape painter in his lifetime. Runciman died in Edinburgh and is buried in
Canongate Churchyard. The grave is unmarked but a stone plaque was erected by the RSA in 1866 on the west-facing wall of the church to his memory (also commemorating his brother John who died in Naples). ==Known works==