Osman III was born in Edirne in 1699. His father was Mustafa II and his mother was Sehsuvar Valide Sultan. After his father was dethroned in 1703, he was brought to Topkapi Palace at the age of four and lived there in custody for a very long time, 53 years. After the death of his older brother Mahmud I, he ascended to the throne in 1754 at the age of fifty-eight as the 25th Ottoman sultan. He enjoyed watching javelin games, rifle and arrow shooting. He loved fruits and drinking coffee. Some days, he would walk around the city in disguise and inspect the people. The Nuruosmaniye Mosque, the foundation of which was laid by Mahmud I, was completed by Osman III. The sultan created many charitable works during his short reign.
Osman III changed the grand vizier six times and high-level administrators many times during his three-year reign. During this period, natural disasters such as minor earthquakes, floods, severe cold and big fires happened in Istanbul. In 1755, the Golden Horn was frozen. In addition, two-thirds of Istanbul was reduced to rubble due to major fires. A relatively calm period was experienced in foreign policy. A friendship and trade agreement was signed between the Ottoman Empire and the Kingdom of Denmark.
Osman III died in 1757 and was buried in the Turhan Valide Sultan Tomb in Istanbul. Since he had no children, Mustafa III became the next sultan.