He was born in 1884 in Izmir, in the Aegean region of Anatolia. His father was Mustantik Resit Bey and mother Cevriye Hanim. On 26th September 1906 he joined the 2nd Army as a superior captain and became a member of Ittihat ve Terakki party.
He also took place in the Operational Army which stopped the 31st of March incident. During World War I he worked as a division manager in the ministry under the War Minister Enver Pasha. In 1915 he was appointed to the 2nd Army Chief of Staff desk and promoted to Colonel on December 14th. He served in the 4th Army at the Caucasian frontier.
On 25th October 1920 he became commander of the Western Frontier and stopped the Cerkez Ethem riot. During the War of Independence he won the 1st and 2nd Inonu campaigns against the Greeks. At the end of World War I he represented T.B.M.M. government in the Armistice of Mudanya and Treaty of Lausanne.
On 30th October 1923 he became the first Prime Minister of Turkey. After the death of Mustafa Kemal Atatürk (10th November 1938) he was elected as the President and carried the title until 14th May 1950.
Between 1950-1960 he stayed in politics as a Parliamenter of Malatya and the leader of the main opposition party. Later he was elected as Prime Minister again, 3 times between 1961-1965, total of 10 times and governed for a total of 16 years and 10 months.
On 20th October 1972 he resigned from his party and became a member of the Republics Senate.
One of his sons, professor Erdal Inonu, became also an active politician during the 80's and 90's in various socialist parties. He passed away on October 31st, 2007.