James Hamilton Langdon Yorke was born on 16 Sep 1884 in Waimate Plains, New Zealand, the son of Katherine Ellen and James Charles Yorke J.P. later of Langton, Durbach, Pembrokeshire.
He was educated at Haileybury School in Great Amwell Herts, 1898-1903 before moving on to Oriel College, Oxford where he achieved a BA. During this time he joined the Pembrokeshire Yeomanry.
He married Violet Mary Vincent on 1 Dec 1910 in St Pancras, London and they lived at 8 Argyll Mansions, Chelsea, London. On the 1911 Census, he and his wife were boarding at Atherton Terrace, Kensington, London.
They had a son James John Simon born 1912 and a daughter Susannah Mary born 1915. He was employed by the British South Africa Company at the outbreak of war.