Sir Harold Edwin Boulton was the elder son of Sir Samuel Bagster Boulton (1830-1918), the founder and chairman of the London Labour Conciliation Board whose baronetcy was created in 1905, and Sophia Louisa Cooper (1837-1900). He had four sisters and one brother. He was educated at Harrow, and at Balliol College, Oxford (B.A. 1881), where he was devoted to music, for some time leading the school choir. On leaving Oxford, he joined the family firm of Burt, Boulton and Haywood, which owned timber, railway and chemical businesses.