He was made a Baronet in July 1938, of Philiphaugh, Selkirkshire, and from 1948 to 1958 he served as Lord Lieutenant of Selkirkshire.
David Leslie, a leading highly experienced soldier and Covenanter, attacked O'Cahan's men as they were just waking up at an encampment in Philiphaugh (near to the site of today's Selkirk Rugby football club ) on 13 September 1645.