On the death of the McGovern chief Brian Mág Samhradháin in 1258, Donnchadh took the chieftaincy.
In 1269 he was murdered by his half-brother or step-brother Tomás Mág Samhradháin in an internecine struggle for the chieftaincy.
The Annals of Ulster for 1269 state- Donnchadh Mag Shamhrudhain rested in Christ.
[4] The Annals of Connacht 1272 state- Donnchad son of Gilla na Naem Mag Samradain was killed by Tomas mac Aeda Mag Samradain, his own brother.
[5] The Annals of the Four Masters 1272 state- Donough, son of Gilla-na-naev Magauran, was slain by his brother Thomas.