Michael (Bulgarian: Михаил) was a Bulgarian nobleman, the son of Tsar Konstantin Tih of Bulgaria and Maria Palaiologina Kantakouzene, niece of emperor Michael VIII Palaiologos of the Byzantine Empire. He was born in 1270, was declared porphyrogennetos (perhaps to block any older sons of Constantine from inheriting the throne), and was crowned co-emperor by his parents in or before 1272.
When his fatherwas killed in battle against Ivailo in 1277, Michael was left as the nominal legitimate emperor of Bulgaria, but he ruled under the guidance of his mother, and his control was quickly restricted to the capital Tărnovo. While much of the provinces fell into the hands of Ivailo, his great-uncle Michael VIII put forward his own pretender to the throne, Ivan Asen III, a son of Mitso Asen of Bulgaria and Maria of Bulgaria.
With Byzantine armies marching north intent on placing Ivan Asen III on the throne, Maria Kantakouzene came to an arrangement with Ivailo, whereby she married her husband's murderer and associated him on the throne together with her son. Ivailo was successful in resisting the Byzantine encroachments until he was blockaded by the Golden Horde of Nogai Khan inside Drăstăr (Silistra) for three months in 1279. Assuming that he was dead, the city nobles opened the gates of Tărnovo to the besieging Byzantine army and accepted Ivan Asen III as emperor.
Together with his mother Maria, Michael was sent into captivity in the Byzantine Empire. He reappeared on the pages of history only about 1302, when a faction of the Bulgarian nobility invited him to recover his throne from Theodore Svetoslav. Although provided with Byzantine military support, Michael proved unable to assert himself in Bulgaria. The date of his death is unknown.