He resided in the castle of Croaghan of the Cups (Irish: Cruachan O'Cúbhrán), now in the townland of Coolnashinny, which is located beside the modern town of Killeshandra.
During Gíolla Íosa's reign, he helped the O'Rourkes capture Cloughoughter Castle from the O'Reillys, although the Sheridan clan recaptured it.
The Annals of Connacht for the year 1282 states Gilla Isa Mag Tigernain, chieftain of the Tellach Dunchada, rested in Christ.
The Annals of Loch Cé for the year 1282 states Gilla-Isa Mac Tighernáin, dux of Teallach-Dunchadha, quievit.
[3][4] Maoilmheadha's children with Brian were Domhnall, Tighearnan, Matha, Donnchadh, Sitriug (d. 1351) and Tomás Mág Samhradháin the Second, who was chief of the McGovern clan until his death in 1340.