In the 1680s he was a supporter of the Catholic James II, he was a Jacobite serving in the Irish Army. Ferrall commanded a regiment based at Boyle, County Roscommon. He led a force of troops to try and stop Lord Kingston's withdrawing Protestant garrison of Sligo from reaching Ballyshannon, but they were driven back near Bundoran. He was reportedly killed during the Siege of Derry in 1689.