His career in Ireland began when in 1598 Robert Devereux, 2nd Earl of Essex appointed him Governor of Carrickfergus, following the death of his brother Sir John Chichester who had been killed at the Battle of Carrickfergus the previous year. It is said that John Chichester was decapitated, and his head used as a football by the MacDonnell clan after their victory. James Sorley MacDonnell, commander of the clan's forces at the Battle of Carrickfergus, was poisoned in Dunluce Castle on the orders of Robert Cecil to placate Chichester.