After graduating from Galatasaray High School in 1910, he studied humanities in the University of Lyon, France, until 1914. After his return to Turkey, he started to work in fields of sociology. In 1918 he was one of the co-founders of the newspaper Akşam.
In 1928 he was elected as member of national parliament from Sivas province . His political success continued and he was elected again for five consecutive times to parliament. He represented Turkey many times in international conferences. Between 1947 and 1950, he was the Minister of Foreign Affairs of Turkey. Sadak also elected as the chairman of Galatasaray in 1928. Although there was no national football league established in Turkey in the 1920s, Galatasaray won an Istanbul League title, while Sadak was the president.
