Yakov Mikhailovich Sverdlov (3 June [O.S. 22 May] 1885 – 16 March 1919) was a Russian revolutionary and Soviet politician. A key Bolshevik organizer of the October Revolution of 1917, Sverdlov served as chairman of the Secretariat of the Russian Communist Party from 1918 until his death in 1919, and as chairman of the All-Russian Central Executive Committee (head of state) from 1917 until his death in 1919.
Born in Nizhny Novgorod to a Jewish family active in revolutionary politics, Sverdlov joined the Russian Social Democratic Labour Party in 1902 and supported Vladimir Lenin's Bolshevik faction from 1903. He was active in the Urals during the failed Revolution of 1905, and over the next decade was subjected to constant imprisonment and exile. After the 1917 February Revolution overthrew the monarchy, Sverdlov returned to Petrograd and was appointed a secretary of the party's central committee. In this capacity, he played a key role in planning the October Revolution, in which the Bolsheviks came to power. Sverdlov became one of the most powerful figures in the Soviet regime, with Lenin, Leon Trotsky, and Joseph Stalin.