[3] He was the eldest child of Robert James Plenderleith who was art master at Harris Academy in Dundee and Harold was consequently educated there, also being school dux.
He then joined University College in St Andrews in 1916 but after two terms went to officer training school due to the First World War becoming a Lieutenant in the Lancashire Fusiliers in 1917.
[7] This department had been created by the museum to address objects in the collection that had begun to rapidly deteriorate as a result of being stored in the London underground railway tunnels during the First World War.
As an archaeologist he was involved in the excavations of the tomb of Tutankhamun in Egypt, Sir Leonard Woolley's site at Ur, and the Sutton Hoo ship burial.
[8] In the Second World War he worked with Sir John Forsdyke on the relocation of precious artefacts from the British Museum into mines and quarries in Wales to avoid bomb damage.