[3] He was supported in his claim by Miler Magrath who suggested that his seniority in the family made him the rightful candidate.
He was able to survive attacks by rival O'Donnell claimants but was unable to gain the support of the Crown for his claims because he was regarded as untrustworthy.
[7] In 1593, he was forced to acknowledge the succession of Hugh Roe after he captured his stronghold of Beleek and executed sixteen of his leading supporters.
[6] Hugh Dubh was still in possession of a large amount of land by the time of the Ulster Plantation.
[citation needed] He is noted for his long life, outliving many of his O'Donnell rivals across several generations.