Mirza was born on November 15, 1899, to a wealthy family in Bengal. He completed his schooling at Elphinstone College in Bombay and later studied at Sandhurst Academy in England for army training. Upon his return in 1919, he joined the British India Army. In 1926, he left the army and joined civil service. He was posted as assistant commissioner in North West Frontier Province and later promoted to district officer in 1931.
Much of his career as a district officer was spent in the tribal areas. Before the creation of Pakistan, he worked for the Ministry of Defense of the Government of India as a joint secretary. At the time of the Partition 1947, he was made a member of the team that was to divide personnel and assets between the Indian and Pakistan armies.
Being the most senior Muslim civil servant in the Indian Ministry of Defense, Mirza was appointed as the first defense secretary of Pakistan. He served in this position for seven years.
When Governor General Ghulam Muhammad decided to enforce Governor’s Rule in East Pakistan in 1954, he appointed Iskander Mirza as governor of the province.
From October 1954 to August 1955, Mirza also served as the interior minister and then as the minister of states and frontier regions in the cabinet of the prime minister Muhammad Ali Bogra.
When the governor general fell ill and went on a leave, Mirza served as acting governor general. However, this temporary charge was soon made permanent. He appointed Chaudhry Muhammad Ali, another bureaucrat, as the prime minister of the country. When the Constitution of 1956 was adopted, the title of the head of state of Pakistan was changed from governor general to president, but the duties and powers associated with the office did not change. The constituent assembly unanimously elected Iskander Mirza as the first president of Pakistan.
Mirza was a civil servant and believed that politicians should have the power to make policies but should not interfere in a country’s administrative affairs. Mirza was an advocate of the One Unit Scheme and did not believe in mixing religion with politics.
In 1958, feeling threatened by the reorganisation of the Muslim League and the alliance of the Awami League with the Punjabi groups, he issued a proclamation dissolving the provincial and federal assemblies and invoked the first martial law in Pakistan.
Mirza remained president and appointed Ayub Khan as the martial law administrator and the supreme commander of the armed forces. Khan, on October 27, 1958, compelled Mirza to leave the country and assumed the title of president, announcing that the martial law would continue in order to give legal cover to certain reforms he wanted to put through.
Iskander Mirza spent the rest of his life in London. He died on November 15, 1969.