Endowed with vast learning, he first held administrative and judicial posts; as secretary at the court of Michael V (1041-42), he enjoyed the favor of Constantine Monomachus (1042-54) who in 1045 appointed him professor of philosophy at the Academy of Constantinople. For nine years he devoted himself to the renewal of Byzantine culture and of the Academy itself. Following the political-religious events that disturbed relations between Byzantium and the Roman Church in the latter years of Monomachus’ reign, he fell into disfavor and, like other officials, became a monk (taking the name Michael). Nevertheless, Empress Theodora repeatedly sought his counsel, and under her successors Psellus returned to the court, playing a predominant role there. In 1071 he took part in the election of Michael VII Ducas, already his pupil, and induced him to reject proposals for union with the Roman Church. Falling again and definitively into disfavor, he died poor and obscure (the date 1078, uncertain, is by some extended by two decades), a victim himself of the political arts and intrigues he had shamelessly employed.
Far more than for his political fortunes, Psellus’ name is linked to that vast movement of restoration of Platonic thought, of which he, albeit with eclectic tendencies, was the guiding spirit at a time when Byzantine culture was decisively dominated by the Aristotelianism of Photius (v.). In this he returned to the speculative impulse of the three Cappadocians and especially of St. Gregory Nazianzen (v.), the only one, in his judgment, to be preferred to Plato (cf. Sathas, Μεσαιωνική Βιβλιοθήκη, IV, p. 111). In this regard he may be considered a precursor of the great Byzantine Platonists who in the 15th century established in Medici Florence, Ficino (v.), the cult of Plato.
Among Psellus’ works are to be noted: *Exposition in Canticum Canticorum*; *De omnifaria doctrina*; *Dialogus de daemonum energia seu operatione*; *De anima celebres opiniones*; *In psychogionam platonicam*; *Exposition in oracula magica quae a Zoroastro proditae*; *Exposition in oracula Chalcidica*; *Compendium in logicam Aristotelis* (which includes the mnemonic verses of the modes of the syllogism).