When Tirlough's father died in 1542, he and his family were quickly pushed aside by the internal politics of O'Neill dominated Ulster.
He is listed as having the ability to raise "50 Horse and 200 foot" soldiers out of his territories at 24 hours' notice to fight.
Tirlough again made a bid for the lordship in the 1590s, but his cousin, Hugh O'Neill, 3rd Earl of Tyrone, bought him off with a gift of territory.
In 1595 the English make reference to Tirlough as being part of the leadership in Ulster, but too old to worry about, and he died sometime after.
These sons were fought in the Nine Years' War raiding neighboring clans, and in the 1608 Rebellion.