Morgan O'Brien was born in Auckland on September 25, 1886 to Charles O'Brien (proprietor of the Alpha Hotel, Kihikihi) and Elizabeth. Charles was born 1855 in Youghal, County Cork, Ireland and died in 1922 in New Zealand. Although O'Brien finished high in the New Zealand civil service examinations in 1904 aged 17, by 1911 he had become a miner at the infamous Waihi mine in the Hauraki District. In 1914 O'Brien enlisted as a field artillery gunner in the main body of the New Zealand Expeditionary Force headed for Egypt and Gallipoli. He survived the war and was discharged in 1919 with rank of sergeant, however his brother Daniel died in hospital of wounds on 15 Nov 1918, just days after the armistice. Morgan's mother died in 1920, and his father died in 1922, all three are buried together in Hairini Catholic Cemetery near Te Awamutu. It was around this time Morgan married Vera Burmester, who was born in New Zealand in 1893, father John Alfred, mother Ada. In the early 1920s Morgan was designing security systems and applied for several British patents relating to shop and bank security. However, in 1925, he left with his wife for Sydney, and then via Vancouver and through Montreal to England (his father-in-law had been born in Canada).