Ali Fethi (Okyar after 1934) was born in the Ottoman town of Prilep in Manastir Vilayet (present-day North Macedonia) to an Albanian family.

[4] His father was İsmail Hakkı Bey, a civil servant in the Ministry of Foreign Affairs who died when Ali Fethi was young.

[7] There he befriended with figures like Ali Fuat (Cebesoy), Şevket, Cafer Tayyar (Eğilmez), Kara Vasıf, and Mürsel.

While on the staff of the Third Army Marshal İbrahim Pasha, he played an important role in the clashes with Greek committee bands, which became more active after the Reval meeting between King Edward VII and Tsar Nicholas II, and in Strebne.[where?]

Upon the suggestion of Rumelia Inspector Hüseyin Hilmi Pasha, he was appointed as the commander of the Salonika Gendarmerie Officer's School on 21 March 1908 and promoted to the rank of "Major".

On 3 July, 1908, a group of 150 people, including Reşneli Ahmed Niyazi began an uprising from which many Rumelian cities joined in revolution.

After demonstrations in places like Salonika, Serres, İştip, Priştina in support of the constitution Ali Fethi and the leading Unionists again gathered at Manyasizade Refik's house.

[14][15] He was appointed the Paris Military Attaché by the Minister of War Mahmut Şevket Pasha on 12 January 1909, but took up his post in March, serving until 1911.

Returning from Istanbul, he accompanied Abdul Hamid II to his house arrest in Salonika, serving as a guard at the Villa Allatini for more than three months.

Due to the Ottoman government's belief that the issue would be resolved through diplomatic means, the CUP leaders decided to take matters into their own hands.

Ten Unionists including Ali Fethi, Mustafa Kemal, Eşref Kuşçubaşı, and Süleyman Askerî gathered at Enver's house.

He also asked for help from SFIO leaders Jean Jaures and Pierre Loti, and the two of them wrote articles criticizing the Italian occupation.

[18] Fethi first reached the port of Sfax in French Tunisia with five military medical doctors and a boatman from Marseille, and arrived in Tripoli on 12 October 1911.

He was appointed chief of staff of the 42nd Division, commanded by Colonel Neşet Pasha, and took to organizing local militia groups against the Italians.

[19] During his activities around Tripoli, on 3 November he reported to the division command that Italian soldiers were abusing the civilian population, and he requested that this situation be protested by the European states.

Battle plans were drawn up for an operation to relieve Edirne, which included an amphibious landing at the Bolayır line and Şarköy.

Fethi's Bolayır Corps participated in the operations to retake Edirne from Bulgaria, but Enver Pasha's troops retook the city first.

He was elected as the secretary general of the CUP in an abortive attempt to liberalize the party, but quickly resigned and sent to Sofia on a diplomatic exile.

The party was banned on 5 May 1919 for being a continuation of the CUP, and a few days later, on 10 March 1919 he was arrested for being a member of a secret Unionist organization, and was exiled to Malta on 2 June 1919.

Learning of his friend's illness, Atatürk assigned his aide Salih Bozok as his companion and arranged for Fethi Bey to receive treatment in Vienna.

He was appointed to as Ambassador to London on 31 March 1934, where he played an important role in the rapprochement between Turkey and the United Kingdom before World War II; he was among the architects of the Montreux Convention.

Shortly after Atatürk's death, in accordance with President İsmet İnönü's policy of reconciliation with his former enemies, he returned to the country and was rehabilitated, being appointed as Deputy of Bolu on 4 January 1939, winning reelection the same year.

British intelligence reports described the couple as “the Turkish Greta Garbo and her ambassador husband with a Tatar’s looks.” They had two kids, a son Osman (1917–2002) and a daughter Nermin (1919–1999).