Ó Cormacáin was a member of an ecclesiastical family based in Síol Anmchadha, in what is now south-east County Galway.
Writing from Loughrea on 5 November 1838, John O'Donovan gave the following account of Abbot Henry Ó Cormacáin: "Henry O'Gormacain was abbot, at the time of the general suppression on Monastries.
He never surrendered the abbey [Clonfert] but continued seized of the temporalities of it till his death, notwithstanding the king had, on the 24th of November in the 35 (XXV(?
Immediately on the death of Henry, William O'Gormacain supported by the sept of the O'Maddens procured the abbey from the popu and kept quiet possession thereof till about the year 1657."
O'Donovan noted that the surname Cormican was then still in existence in the parish of Abbeygormican.