Kasyan graduated from Leipzig commercial institute and Berlin University in 1904. PhD on commercial and philosophical sciences. He was a Communist party member from 1905. One of the founders of Armenian bolshevik press in 1905, the leader of Tbilisi communist party organization in 1912-14. In 1919-20 - chairman of Russian Communist (Bolshevik) party Armenian committee. Since the November, 1920 - a member of Armenian Communist Party Central Committee and chairman of the Revolutionary Committee of Armenia, signed the declaration of Sovetization of Armenia. On December 2, 1920 V.I. Lenin sent him a telegram welcoming the establishment of Soviet Armenia.
In 1927-31 he was the chairman of Transcaucasian Soviet Federative Socialist Republic's Central Executive Committee (government), in 1928-30 - also the chairman of Armenian SSR Central Executive Committee. He was an elected member of all-Soviet Central Executive Committee.
- Sarkis Kasyan, 1967, 10 min., dir. R. Frangulyan