Sir Ian Standish Monteith Hamilton was born on January 16, 1853, in Corfu, Greece.

He was a British Army officer. He was educated at Wellington College, Berkshire, and the Royal Military College, Sandhurst. In 1871, he received a commission as an infantry officer with the Suffolk Regiment, followed by service in India, where he took part in the Anglo-Afghan War. During the First Boer War (1880–1881), he was wounded at the Battle of Majuba and returned to England to recover. In 1882, he was made captain and served in the Nile Expedition (1884–1885), then in Burma (1886-1887), Bengal (1890-1893), and India (1895-1898). Upon his return to England in 1898, he was appointed Commandant of the School of Musketry at Hythe. During the Second Boer War (1899-1902), he commanded the infantry at several battles and was promoted to major general. In 1901, Hamilton was appointed Military Secretary at the War Office and was knighted as a Knight Commander of the Order of the Bath in 1902. He was promoted lieutenant-general and served as Quartermaster-General to the Forces (1903-1904). He was the military attaché of the British Indian Army, serving with the Japanese army in Manchuria during the Russo-Japanese War (1904–1905). In 1914, he was appointed the Commander-in-Chief, Home Army. He commanded the Allied Mediterranean Expeditionary Force, with orders to gain control of the Dardanelles straits from the Ottoman Empire and to capture Constantinople. After suffering heavy casualties, he was recalled in 1915 and was given no further command. Hamilton received the honorary Doctor of Laws (LL.D) from the University of Glasgow in 1901. A statue of Lt.-Gen Hamilton stands on the Boer War memorial in Cheltenham, England.

In 1887, he married Lady Jean Miller Muir (1861–1941). He died on October 12, 1947, in London, England.