In 1652 he married Cromwell’s daughter, Bridget, widow of Ireton, and became commander-in-chief in Ireland, to which title that of lord deputy was added. The chief feature of his administration, which lasted from September 1652 till September 1655, was the settlement. of the soldiers on the confiscated estates and the transplantation of the original owners, which he carried out ruthlessly. He showed also great severity in the prosecution of the Roman Catholic priests, and favoured the Anabaptists and the extreme Puritan sects to the disadvantage of the moderate Presbyterians, exciting great and general discontent, a petition being finally sent in for his recall.
Fleetwood was a strong and unswerving follower of Cromwell's policy. He supported Cromwell's assumption of the position of Lord Protector and his dismissal of the parliaments. In December 1654 he became a member of the council, and after his return to England in 1655 was appointed one of the major-generals. He approved of the Petition and Advice, only objecting to the conferring of the title of "king" on Cromwell; became a member of the new House of Lords; and supported ardently Cromwell's foreign policy in Europe, based on religious divisions, and his defence of the Protestants persecuted abroad. He was therefore, on Cromwell’s death, naturally regarded as a likely successor, and it is said that Cromwell had in fact so nominated him. He, however, gave his support to Richard Cromwell's assumption of office, but allowed subsequently, if he did not instigate, petitions from the army demanding its independence, and finally compelled Richard by force to dissolve parliament.
His project of re-establishing Richard in close dependence upon the army met with failure, and he was obliged to recall the Long Parliament on 6 May 1659. He was appointed immediately a member of the committee of safety and of the council of state, and one of the seven commissioners for the army, while on 9 June 1659 he was nominated commander-in-chief. In reality, however, his power was undermined and was attacked by parliament, which in October declared his commission void. The next day he assisted Lambert in his expulsion of the parliament and was reappointed commander-in-chief. On Monk's approach from the North, he stayed in London and maintained order. While hesitating with which party to ally his forces, and while on the point of making terms with King Charles II, the army on 24 December restored the Rump Parliament, whereupon Fleetwood was deprived of his command and ordered to appear before parliament to answer for his conduct.
The Restoration therefore took place without him. He was included among the twenty liable to penalties other than capital, and was finally incapacitated from holding any office of trust. His public career then closed, though he survived till 4 October 1692.
Original text from 1911 Encyclopaedia Britannica