At the age of 42, in 1918 he became Minister of War and Commander of the Ottoman Army. In 1920, he followed Mustafa Kemal to Samsun, and supported him throughout the Turkish War of Independence. His support provided Mustafa Kemal with the full support of the Armed Forces, which was reduced to two armies in the aftermath of the disarmement dictated by the Treaty of Sèvres. These two armies were under the command of Kazım Karabekir on the Eastern Front based in Erzurum and Ali Fuat Cebesoy on the Western Front based in Ankara. Fevzi Çakmak was one of the few significant generals of the Turkish War of Independence.
Fevzi Çakmak took control of the Army after the Turkish loss in Kutahya-Altıntas under Ismet Inonu and was able to stop the retreat of the Turkish Army afterwards and beat the invading Greek Armies at the Battle of Sakarya on the outskirts of Ankara. Fevzi Çakmak and Mustafa Kemal planned and commandeered the Battle of Dumlupınar, and on August 31, 1922, he was promoted to rank of Field Marshal (Mareşal) along with Mustafa Kemal. They were and still are the only Field Marshals Turkish Republic had up till now. So even today, an unspecified nickname Mareşal(Field Marshal) means Fevzi Çakmak. Before the establishment of the republic, he was the prime minister of the government of the Grand National Assembly of Turkey from January 24, 1921 until July 9, 1922. He quit politics by resigning from the parliament in 1924. Fevzi Çakmak served as the Chief of the General Staff of the Turkish Armed Forces from March 3, 1924 until his retirement on January 12, 1944. He died on April 12, 1950 and was laid to rest in Eyüp, İstanbul. He has a memorial burial place in the Turkish State Cemetery in Ankara.