Ellison was born in York and later lived in Leeds, England. He first joined the British Army as a regular soldier in 1902 – but had left by 1912, by which time he had become a coal miner, and when he married Hannah Maria Burgan in Nottingham. Sometime just before the outbreak of war he was recalled to the army, joining the 5th Royal Irish Lancers and serving in the army from the very start of the war. He fought in the Battle of Mons in 1914, and several other battles including the Battle of Ypres, Battle of Armentières, Battle of La Bassée, Battle of Lens, Battle of Loos, and Battle of Cambrai on the Western Front.