Saydam became the vice-president of the Department of Health of the Ministry of War on 1 December 1913 and was promoted to the rank of major on 1 June 1915.

He attended to Erzurum and Sivas Congresses, came to Ankara with the delegation committee and joined to the opening ceremony of the Grand National Assembly of Turkey with the elections held for the first term as the deputy of Bayazıt on 23 April 1920.

Being elected as İstanbul deputy, he officiated as the Minister of Health under the cabinet of İsmet Pasha in 2nd, 3rd, 4th, and 5th sessions.

After the death of Atatürk, at the Second Bayar Government formed on 11 November 1938, Saydam performed as the Minister of Interior and was assigned as the general secretary of the Republican People's Party.

He was appointed to Prime Ministry of the 11th and 12th government of Turkey by President İsmet İnönü as İstanbul Deputy at the 6th session elections on 25 January 1939.