Smbat was the son of Manuel Bagratuni. He is first mentioned some time in the 580s, when the Byzantine emperor Maurice (r. 582–602) requested the Armenian nobles to raise cavalry for service in his wars against the Avars. Smbat and Sahak Mamikonian led a thousand-strong unit each to Constantinople, where they were richly rewarded and sent home. Sebeos also adds that Maurice supposedly adopted Smbat at this occasion. In 589, however, Smbat led a rebellion against the Byzantines, was captured and sent to Constantinople, where he was condemned to death and was thrown to be devoured by the beasts in the Hippodrome of Constantinople. He was pardoned at the last minute by Maurice, who then banished him to some "distant islands" and later to Africa.