Kâzım Orbay was born in Smyrna (present day: İzmir), Ottoman Empire in 1887. He graduated from Mühendishâne-i Berrî-i Hümâyûn (Imperial School of Military Engineering) and joined the army in the rank of an artillery lieutenant in 1904. After finishing the Staff College in 1907, he became a staff officer. In 1908, he attended military courses in Germany. In 1912-1913, he fought in the Balkan Wars. He was appointed chief adjutant of the Ministry of War in the Ottoman cabinet and served under Enver Pasha during World War I. In 1915, he was the Ottoman representative in the Niedermayer–Hentig Expedition to Afghanistan. He presented to Emir Habibullah Khan the Ottoman Sultan's declaration of jihad: a call to all Islamic peoples (including Afghanistan) to join the Central Powers and attack the Allies. Afghanistan was to attack British India starting from the city of Peshawar however this plan never came into effect.
In 1926, he was promoted to Korgeneral and appointed vice chief of the general staff. During 1928 and 1929, Kâzım Orbay served as Chief of the General Staff of the army of Afghanistan. Following his return to Turkey, he held high-ranking military posts; in 1935, he was promoted to Orgeneral.
Succeeding Fevzi Çakmak, he served as Chief of the General Staff of the Turkish Armed Forces from 12 January 1944 to 23 July 1946, when he resigned.
Kâzım Orbay retired on 6 July 1950. After the military coup of 1960, he was elected senator in 1961 and served as the president of the parliament.
He was married to Mediha Hanım, sister of Enver Pasha, and they had a son named Haşmet. On 16 October 1945 Haşmet Orbay murdered physician Naci Arzan. The investigation of the Ankara Murder turned into a political scandal involving the Republican People's Party apparatus.
