Raised by his mother in County Galway, he lived most of his life in exile from his kingdom, looking for allies to support his claim as king of West Breifne in opposition to his half-brother Brian Oge O'Rourke.
Under English law, O'Rourke was the legitimate heir to the kingship of West Breifne and, as a son of a wealthy pro-English family, was favoured by the crown government in Dublin from the outset to inherit his father's title.
Teigue's inheritance was thrown into further doubt when Lord President Richard Bingham, who effectively wanted to end the O'Rourke dynasty, occupied West Breifne in 1590 and ousted Sir Brian, who was executed for treason at Tyburn the following year.
[2] However, as Teigue's hugely influential family continued to push his claim, gaining backers like Lord Treasurer Thomas Butler, Brian Oge switched back to the Irish alliance believing the English assurances to be disingenuous.
During his exile Teigue continued to make frequent contact with the English through mail:"I pray the Lord that I may never enter the kingdom of Heaven if I do not spend my blood, flesh and all that I can get in the world to do Her Majesty's service.
By late 1601 the Irish alliance had suffered a string of defeats and Brian Oge and O'Donnell travelled south to assist the 4th Spanish Armada which made landfall in Munster.
Teigue was given command of 3,000 English soldiers by the government and was sent along with Rory O'Donnell and Henry Folliott to retake West Breifne at the end of March 1603.
[5] The defeat of the Irish in the Nine Years' War heralded the end of the Gaelic Political order and the powers of the native kings were severely reduced.