Dudley was the son of the Staffordshire-born Sir Nicholas Bagenal who had settled in Ireland in the 1550s, creating a power base around Newry in Ulster thanks to the support of the dominant Gaelic lord Conn O'Neill, 1st Earl of Tyrone.
He served as an officer in the Irish Army force sent north to Ulster to maintain order in the 1580s, being stationed in Clandeboye.
This appeared to be a revenge attack for the killing of a leader of the Kavanaghs four months earlier, which both Bagenal and his brother-in-law Henry Heron had taken part in.
His death led to a political dispute between Sir Nicholas Bagenal and the Lord Deputy John Perrot who refused to grant Sir Nicholas custody of his grandson, Dudley's son George Bagenal, who was made a ward of court.
[4] His family remained influential in Carlow, and were related to other powerful Bagenals in other parts of the country many of whom became Roman Catholics despite the Penal laws.