Born in August 1881, in Altrincham, Cheshire, he was the son of James Kinder Bradbury and Grace Dowling. He attended the Royal Military Academy, Woolwich, as a cadet, passing out to join the Royal Artillery as a second lieutenant on 2 May 1900. He was promoted to full lieutenant on 3 April 1901, and in January 1902 was seconded for service with the Imperial Yeomanry in South Africa for the Second Boer War, and appointed a lieutenant with the 31st Battalion. The war ended six months later, and Bradbury resigned his appointment in the Imperial Yeomanry in November 1902, leaving Port Natal for Aden on the SS "Dominion" the same month. He was posted to the 127th Battery RFA in 1904.