Smith was involved in the management of the family business, W H Smith, which was founded by his grandfather, William Henry Smith. He inherited sole control of the business from his father in 1891 and passed it on to his son. Smith was commissioned Lieutenant in the 2nd Buckinghamshire Rifle Volunteers (Eton College) in 1885, but resigned in 1887. In 1891 he was commissioned Second Lieutenant in the Royal 1st Devon Yeomanry. He was promoted Lieutenant in 1892, Captain in 1895, Major in 1902, and Lieutenant-Colonel in 1914. He served with the Imperial Yeomanry during the Boer War.