Born in Sialkot, British India, Khan was educated as a lawyer at the GC University and the King's College London. Khan went on to serve as a member of Punjab Legislative Council between 1926 and 1931, and was a delegate in 1930, 1931, and 1932 to the Round Table Conferences on Indian reforms in London, England. He became a member of the All-India Muslim League which led the Pakistan movement and served as the league's president between 1931 and 1932. In 1935, he became the Minister of Railway of British India, and sat on the British Viceroy's Executive Council as its Muslim member from 1935 to 1941. In 1939 he travelled to Geneva to represent India at the League of Nations and in 1942 became the Agent-General of British India to China. In September 1941, Khan became a judge on the Federal Court of India and remained on the court until the partition of India.
Khan became one of the most vocal proponents of Pakistan and led the case for the separate nation in the Radcliffe Commission which drew the countries of modern-day South Asia. He moved to Karachi in August 1947 and became a member of Pakistan's first cabinet serving as the country's debut foreign minister under the Liaquat administration. He remained Pakistan's top diplomat until 1954 when he left to serve on the International Court of Justice and remained on the court as a judge until 1958 when he became the court's vice president. He left the Hague in 1961 to become the Permanent Representative of Pakistan to the United Nations, a position he served until 1964.
During his time at the UN, he also represented the State of Palestine in a de facto capacity. He left the UN in 1964 to return to the ICJ and, in 1970, he became the first and only Pakistani to serve as the President of the International Court of Justice, a position he maintained until 1973. He returned to Pakistan and retired in Lahore where he died in 1985 at the age of 92. Khan is considered as one of the leading founding fathers of Pakistan and a prominent member of the Ahmadiyya Community in Pakistan. He authored several books on Islam both in Urdu and English.
Khan was born on 6 February 1893 in Sialkot and acquired his early education at the American Missionary School in Sialkot. Khan's father was Ch. Nasrullah Khan who was the leading attorney of his native city of Daska and a companion of Mirza Ghulam Ahmad founder of the Ahmadiyya Community. His father belonged to the Sahi Jat clan while his mother was of the Bajwa Jat clan and from both sides were Zamindars. Sir Zafarullah Khan was very close to his mother and inspired by her courage and devotion to her religion and even wrote a book called "My Mother". He studied at Government College, Lahore and received his LL.B. from King's College London, in 1914. He was called to the bar at Lincoln's Inn, London. He practised law in Sialkot and Lahore, became a member of the Punjab Legislative Council in 1926.
Muhammad Zafarullah Khan was elected a member of the Punjab Legislative Council in 1926 and presided at the Delhi meeting of the All-India Muslim League in 1931, where he advocated the cause of the Indian Muslims through his presidential address. He participated at the Round Table Conferences held from 1930 to 1932 and became the Minister of Railways in May 1935. In 1939, he represented India at the League of Nations. He was appointed the Agent General of India in China in 1942 and represented India as the Indian Government's nominee at the Commonwealth Relations Conference in 1945, where he spoke on India's cause for freedom.