[2] A friend and correspondent of Michael Psellos, Constantine and his brother Nikephoros were among the supporters of Isaac I Komnenos when he rose in revolt to seize the throne in 1057, and went on to occupy senior offices in the Byzantine hierarchy.
[2][3] It was probably under Constantine's tenure that the latter office acquired the epithet "megas" ("grand"), and was confirmed as the Empire's senior-most judicial authority.
He therefore had Eudokia swear publicly that she would not remarry nor appoint any co-regents over her under-age sons with Constantine other than the latter's brother John Doukas, an oath that she would soon break, however, with her marriage to Romanos IV Diogenes.
[1] According to genealogy of the 12th-century writer John Tzetzes, Constantine Keroularios married a Georgian lady, a relative of the empress Maria of Alania.
[1][7][8] Constantine had also several sons, of whom Michael Keroularios was the most prominent: he likewise became megas droungarios tes viglas and married into the Komnenos dynasty, but defrauded his other brothers of their father's inheritance.