Henry, a distinguished general and statesman of the English Commonwealth, was the eldest son of German Ireton of Attenton, in Nottinghamshire, and was born in 1610. He was intended for the English bar, and after graduating at Oxford, entered the Middle Temple as a student of law. But the outbreak of the civil war completely altered his plan of life. He offered his sword to the parliament, and through the interest of Cromwell, whose daughter Bridget he had married, he obtained rapid promotion. At Naseby he commanded the left wing of the parliamentary troops, and though he fought both bravely and skilfully, he was completely overpowered by the furious onset of Rupert, and taken prisoner. Cromwell, however, with his Ironsides, retrieved the fortunes of the day, and Ireton regained his freedom some hours after he had lost it. In the subsequent proceedings of the parliament he took a leading part, was one of those who clamoured most loudly for the death of the king, and, when it was decided upon, signed the warrant for his execution. He next accompanied Cromwell into Ireland, aided him zealously and effectively in all the military operations, and when his chief was called away to the campaigns against Scotland, remained behind to complete the reduction of Ireland with the title and powers of lord-deputy. In this office success attended his diplomatic as well as his military plans; and his character for severity, or, as his enemies called it, cruelty, contributed not a little to terrify his foes into submission wherever he went. In the midst of his victorious progress he was cut off by the plague at Limerick, November 15, 1651. His death was sincerely regretted, and his loss deeply felt by his party, who revered him as a good soldier, an able statesman, and a saint. His body was embalmed and conveyed to England, where it was buried in Henry the Seventh's chapel in Westminster Abbey. After the Restoration his remains were disinterred, exposed on the scaffold, and afterwards publicly burned at Tyburn. By Bridges Cromwell (who after his death became the wife of Fleetwood) he had one son and four daughters, who all survived him.

Ireton's abilities both in peace and war are not denied even by the keenest partisans of the monarch whose death he had a "main finger" in bringing about. Cromwell, whose insight into character was unerring, had great faith in his judgment, and entrusted him with drawing up all the more important public acts, memorials, and documents of his party. The legal skill and knowledge which these displayed gained for their author the surname of "the scribe." Hume and the royalist historians are fond of describing Ireton as artful, designing, unscrupulous, and hypocritical; but they hold similar and even more offensive language towards Ireton's master, and posterity has now reversed their verdict in both cases.