Piers Butler, 2nd Baron Dunboyne was the son of Thomas Butler, 1st Baron Dunboyne and Synolda le Petit. He married Catherine de Burgh, daughter of unknown son de Burgh, before 1353. He died on 5 August 1370.
He succeeded to the title of 2nd Baron Dunboyne [I., 1324] on 9 October 1329.1 In 1366 he was called to the Irish Parliament