Henry Izard was educated at Lancing College, and New College, Oxford. In 1914, he was selected for the post of Assistant District Commissioner in the East Africa Protectorate (Kenya). When World War I broke out, he was refused permission to join up in England. However, in 1915, he resigned from his post and joined the Royal Flying Corps (later the Royal Air Force) and served with them in Tanganyika (Tanzania), Egypt, Persia (Iran), and Mesopotamia (mainly Iraq). He returned to East Africa in 1919 as Assistant District Commissioner in Kenya Colony.

Izard was called to the Bar of the Inner Temple in 1929 and was promoted to District Commissioner in 1931. In 1936, he was seconded to Nairobi as Resident Magistrate and the following year was appointed Officer in Charge in Turkana Province and promoted to Senior District Commissioner. In 1938, he was seconded again, this time as Commissioner of Mines, and in 1939 he was nominated as an Official Member of the Legislative Council.

On the outbreak of World War II, Izard again wished to resign but was ordered to remain in Kenya to work on the Geological and Mineral Survey for minerals required for the war effort. He became a Member of the Nairobi Municipal Council in 1941 and in the same year was promoted to Provincial Commissioner. In 1944, Izard took up the temporary post of Public Relations Officer but retired from government service the following Feb in order to become Executive Officer of the newly formed Kenya Elector's Union.

In Jan 1946, Izard returned to England with his wife and family, 'to examine on the spot and report as to the desirability of establishing representation in London on behalf of the Electors' Union. From 1952 to 1967, he also became the London Representative for the Tea Boards of Kenya, Tanganyika (Tanzania), and Uganda.