Lawrence entered Emmanuel College, Cambridge, as a fellow-commoner in 1622, and graduated B.A. in 1623, M.A. in 1627. There is no authority for Wood's assertion that he received part of his education at Oxford. At college he belonged to the puritan party. He was not only lineally allied to Cromwell, but was at one time his landlord, as he let to him his house and farm at St. Ives from 1631 to 1636 (Masson, Life of Milton, iv. 645). About 1638 he retired to Holland, probably to avoid the severity of the ecclesiastical courts. He returned in 1641, but was abroad again at the outbreak of the war (see dedication of his Communion and Warre with Angels). In December 1645 he was at Arnheim in Guelderland, and at Altena in January 1646 (Harl. MS. 374). On his final return to England he replaced one of the 'disabled' members for Westmoreland on 1 Jan. 1645-6 (Official Return of Lists of Members of Parliament, pt. i. p. 495). In July 1646 he was nominated one of the commissioners for the preservation of peace between England and Scotland (Thurloe State Papers, i. 79), and on 17 March 1647-8 he became a commissioner of plantations (Hist. MSS. Comm. 7th Rep. pt. i. p. 15 b). Greatly to Cromwell's annoyance, Lawrence expressed strong disapproval of the proceedings against Charles I. In 1652, being then styled 'colonel.' he visited Ireland as a commissioner for that kingdom (Cal. State Papers, Dom. 1651-2 pp. 487, 537, 1652-3 p. 55). On 14 July 1653 he was appointed one of the council of state (ib. 1653-4, p. 14) and placed on several committees. In the parliament of 1653 Lawrence sat for Hertfordshire, and after its dissolution was placed on Cromwell's new council of state, his salary being 1,000l. a year. In November 1653 the council of state appointed him keeper of the library at St. James's House. At the second meeting of the council he was made chairman for a month, but by a subsequent order of Cromwell, dated 16 Dec. 1653, he became permanent chairman, with the title of 'lord president of the council' (Thurloe, i. 642 ; Cal. State Papers, Dom. 1653-4, p. 298). In the satirical 'Narrative of the Late Parliament.' 1658, Lawrence is said to have been made president to win over, or at least keep quiet, 'the baptized people, himself being under that ordinance' (reprint in Phœnix Britannicus, 1731, p. 125). Milton, however, in his second 'Defensio Populi Anglicani.' 1653-1654, bears eloquent testimony to Lawrence's ability and learning. In 1654 Lawrence strove to assist Lord Craven in recovering his English estates, which had been confiscated in 1650-1, and he had some correspondance with Elizabeth, queen of Bohemia, on the subject (Thurloe, ii. 139).
In Cromwell's parliament of 1654 Lawrence was again returned for Hertfordshire (Return of Members of Parliament, pt. i. p. 500), and in that of 1656 he was chosen for both Colchester and Carnarvonshire (ib. pt. i. p. 506). He elected to serve for Carnarvonshire, and continued to represent it until his elevation to Cromwell's House of Lords in December 1657 (Prestwich, Respublica, pp. 10, 15). On the death of Cromwell in September 1658 he declared Richard his successor and ordered his proclamation (cf. his letter in Hist. MSS. Comm. 3rd Rep. p. 254). He ceased to act as president in July 1659.
After the Restoration Lawrence withdrew to Thele, otherwise Goldingtons, a manor in the parish of Stanstead St. Margaret, Hertfordshire, which he inherited on the death of his son Edward in 1657. There he died on 8 Aug. 1664, and was buried in the church (monum. inscript. in Cussans, Hertfordshire, 'Hundred of Hertford.' p. 138). By his marriage, on 21 Oct. 1628, to Amy, daughter of Sir Edward Peyton, knt. and bart., of Iselham, Cambridgeshire, he had seven sons and six daughters (Waters, Chesters of Chicheley, i. 243 ; Nichols, Collectanea, iii. 311). His wife's extraordinary piety proved a fertile source of cavalier satire. To their eldest son (Edward or Henry) Milton addressed in the winter of 1655-6 his twentieth sonnet (Masson, v. 235). A drawing of Lawrence is inserted in the copy of Clarendon's 'History of the Rebellion' in the library at Buckingham Palace; it has been engraved by Richard Cooper (Granger, Biog. Hist. of England, 5th edit. iii. 853).
Lawrence was author of: 1. 'Of Baptisms' [anon.], 8vo [Rotterdam], 1646 ; another edition entitled 'A Pious and Learned Treatise of Baptism.' 4to, London, 1649. 2. 'Of our Communion and Warre with Angels : being certain Meditations on that subject, bottom'd particularly on Ephes. vi. 12 ... to the 19.' 4to [Amsterdam], 1646 ; another edition, bearing a different imprint, was issued during the same year. The treatise is commended by Isaac Ambrose in the sixth section of the prolegomena to his 'Ministration of, and Communion with, Angels.' first published about 1660, and also by Richard Baxter, in his 'Saints' Rest.' 12th edit. p. 238. 3. 'Some Considerations tending to the Asserting and Vindicating of the Use of the Holy Scriptures and Christian Ordinances; . . . wherein . . . the Ordinance of Baptisme . . .is manifested to be of Gospell-Institution, and by Divine appointment to continue still of Use in the Church.' 4to, London, 1649;