The second son of Roger Boyle, 2nd Earl of Orrery, and his wife Lady Mary Sackville (1647–1710), daughter of Richard Sackville, 5th Earl of Dorset, he was born at Chelsea. He was educated at Christ Church, Oxford, and soon distinguished himself by his learning and abilities. Like the first earl, he was an author, soldier and statesman. He translated Plutarch's life of Lysander, and published an edition of the epistles of Phalaris, which engaged him in the famous controversy with Bentley. He was a member of the Irish Parliament and sat for Charleville between 1695 and 1699. He was three times member for the town of UK Parliament constituency; and on the death of his brother, Lionel, 3rd earl, in 1703, he succeeded to the title.