He was yst s of Brig John Wesley Harper GOW CBE 1898-1986 sometime head of that Scots gentry family in Howwood and Frances Jean d 1975 d of James BEGG of Westlands, Paisley. He m 1961 Dora Heather Graham b 1938 d of Lt-Col Douglas Graham MONCRIEFF OF KINMONTH MC 1893-1983 sometime head of that Scots gentry family and Henrietta Doreen 1900-87 d of Montagu Rodney ST JOHN 1861-1944 (2xgt gs of 2nd Viscount BOLINGBROKE & [3rd] ST JOHN 1732-87, as well 2xgt gs of 6th Baron CRAVEN 1738-1791 and 1st Baron RODNEY 1719-92, etc) and Theodora Mary Land (29 Oct)1876-1958 d of Henry Northage Land JAMES c1843-(19 Dec)1876 and Jane Emma Bethell PRITCHARD c1853-1933, and had three sons:
1. Alastair John Moncrieff b 1963
2. Jeremy Douglas Moncrieff b 1965: m 2007 ref 417/133 Cupar Anona Marion SIMPSON-GREIG b 1978 ref 421/50 Kirkaldy.
3. Colin Rodney Moncrieff b 1968