Cromwell, Henry (1628–74), soldier and administrator, was born 20 January 1628 at Huntingdon, Cambridgeshire, England, fourth son of Oliver Cromwell (qv) and Elizabeth Cromwell (née Bourchier). He fought only in the closing stages of the English civil wars. In 1647 he was a colonel. In 1649 he was named to command a horse regiment in his father's Irish army, but may not have arrived in Ireland till the following year. In April 1650 he, in company with Roger Boyle (qv), Lord Broghill, defeated the earl of Inchiquin (qv) near Limerick. His link with Ireland was renewed when, in July 1653, he was chosen as one of four representatives for Ireland in the nominated assembly that convened at Westminster. In February 1654 his father, now protector, sent Henry to report on the disorders spreading through the Irish administration and army. He astringently analysed the weaknesses of the lord deputy, Charles Fleetwood (qv), his own brother-in-law. Impatient of the scruples of godly radicals over the institution of government by a single person – his father – he endeared himself to the longer established and more conservative protestants in Ireland, notably Broghill. The latter asked that Henry be added to the Irish council and appointed to command the army in Ireland. In December 1654 he was named to the council, but voyaged to Dublin to discharge his duties only in July 1655. An awkward period followed. Fleetwood returned to London in September 1655 where, still lord deputy, he offered a focus for malcontents.
Meanwhile in Ireland Henry Cromwell, technically Fleetwood's subordinate, struggled to strengthen English authority over Ireland and to discipline the forces. He cultivated politiques, sought advice from grandees within the pre-war protestant community like Broghill, and toured parts of the island. Government took on more traditional aspects, as institutions such as the four courts in Dublin, the commission of the peace, municipal corporations, and parochial ministry were revived. He was also chosen as chancellor of Dublin University, the interests of which he espoused. Nevertheless, he could not lessen dependence on an army of occupation, nor the costs of supporting it, especially once a Spanish war threatened Ireland with invasion in 1656. Furthermore, his freedom to initiate policies was restricted, owing to ultimate control exerted by the protector and council of state in London. In Dublin he was obliged to work through the council. Most of all he was hampered by his father's hesitation about substituting him for Fleetwood as lord deputy, a hesitancy that arose from Oliver Cromwell's distaste for advancing members of his immediate family.
Only on 16 November 1657 was he appointed lord deputy. His elder brother, Richard, having succeeded Oliver Cromwell as protector, advanced Henry to be lord lieutenant and governor-general on 6 November 1658. In so far as he was able to modify the most draconian and impracticable policies, such as the proposed transplantation of much of the surviving catholic population to Connacht, it was by stealth. He aligned himself closely (some thought too closely) with the ‘carnal old protestants’, such as the Boyles in Munster. Believing that the English regime in Ireland would be stabilised only when it had grounded itself securely among such groups, he also associated himself zestfully with the project close to Broghill's heart: the creation of a Cromwellian monarchy. Even within the protestant community of Irish landowners, and notwithstanding admiration for Henry's winning ways, collaboration with the Cromwellian authorities was tempered by uncertainty as to how long it would survive. Some hoped that Henry rather than the feebler Richard might be named to succeed Oliver as protector. Critics accused him of impetuosity and inexperience. He himself confessed to a hot temper. His brusque disavowal of sectaries and sentimental republicans heightened hopes in 1659 that he might declare for the exiled Charles Stuart.
At the collapse of his brother's protectorate he was ordered back to England. In June 1659 he meekly complied, and retired to his Cambridgeshire estates. He played no discernible part in the sequence of events that culminated in Charles II's restoration. His obvious concern was to safeguard his own position. To that end he exploited the contacts that he had developed in the 1650s with those now powerful, conspicuously the duke of Ormond (qv), Roger Boyle (now earl of Orrery), and the 1st earl of Clarendon. The Irish act of settlement of 1662 specifically confirmed his title to the lands that he had earlier been awarded in Meath and Connacht. Through his former secretaries still in Ireland, Robert Gorges, Robert Wood, and William Petty (qv), these properties were overseen. The English government continued to keep an eye on him. In contrast with the forwardness that had won him enemies as well as admirers in the interregnum, in the 1660s his self-effacement saved him from any serious interference. He died on 23 March 1674. His burial place in Wicken church, Cambridgeshire, is marked by a simple tablet.
He married (10 May 1653) Elizabeth, daughter of Francis Russell (later knighted by Cromwell) of Chippenham Park, a Cambridgeshire squire. His heirs seem to have quickly divested themselves of the Irish holdings and so severed any residual link with the country that he had governed from 1655 to 1659. Two drawings of him are in the Ashmolean Museum, Oxford; a portrait by Robert Walker, in the British government collection, reproduced as the frontispiece of R. W. Ramsey, Henry Cromwell (1933), was then at Chequers, Buckinghamshire.
Letters addressed to Cromwell as lord deputy are in BL, Lansdowne MSS 821–3. Other papers are in the Cambridgeshire county record office, Huntingdon branch, 731 dd Bush. His letters from Ireland are included in T. Birch (ed.), A collection of the state papers of John Thurloe, esq. (7 vols, 1742).