Born on 1872 in Tomna (a village north of Bayburt, which is modern-day Turkey), Arshag Nersesian, later given the pseudonym Sebouh, became involved in the revolution while still very young. He received his education in Trebizond (prior to World War I, the vibrant Armenian community of Trebizond numbered 30,000) and showed early aptitude as a craftsman.
In 1889, he left for Constantinople. In 1894, General Sebouh left the Hunchaks and joined the Dashnaktsutyun. He later became the leader of the Dashnaktsutyun. As a member of ARF (Armenian Revolutionary Federation) he became a commander under General Ozanyan. In 1907, Sebouh participated in the Dashnak party congress at Vienna.
As the leader of the ARF and the head of the Dashnaktsakan formation, he took part in the decisive battle of Sardarabad and later went on to help the Armenians besieged in Baku. In 1919, General Sebouh was elected to the Parliament.
General Sebouh was also known for assassinating traitors, driving the Bolsheviks out (May, 1920), and crushing the Alexandropol Soviet. In 1894, he took part in the uprisings in Sasson as well. Sebouh took part in battles at Tabek, Shenik and Semal; where he was later wounded. He also took part in battles in Tadvan, Aghtamar Island and Van.
General Sebouh and General Antranik Ozanyan took battles in Khoy, Dilman, and Salmas (West Azerbaijan, Iran) in 1914–1915. On December 20, 1920 General Sebouh took refuge in Tiflis (Georgia) where he was soon joined by the majority of the members of the Dashnak bureau, who set up a liberation committee there.
In Tiflis, General Sebouh assumed leadership of a force of 500 volunteers which was sent to Salmas, Persia (Iran).
Comrade Garo sent General Sebouh in 1921 to Boston, Mass. where he joined Aharon Sachaklian.
General Sebouh became the first Armenian officer to come to the United States and obtain a United States loan to rehabilitate the Armenian army. In Boston, General Sebouh was financing Soghomon Tehlirian and Operation Nemesis, which led to the assassination of Talat Pasha.
Sebouh continued his tour of the United States as a field worker of the ARF (Armenian Revolutionary Federation), which was trying to keep the dream of independence alive. He helped spread the roots of the ARF throughout the United States. He was the head of the "secret special" mission in the United States, having taken over its direction at the request of Armen Garo (Psadermadjian).
Sebouh eventually settled permanently in Detroit, where he maintained a grocery business. He was one of the first Armenian successful merchants in the United States. In 1936 he and his family moved to New York. At the age of 66, he died on July 31, 1940, a venerated member of the community. General Sebouh's sons joined Gen. Nzhdeh's (Njteh) Tseghakrons.
On November 20, 2014, the remains of General Sebouh were ceremonially buried in Yerevan’s military cemetery at Yerablur.