Watson was a member of an extended network of families whose links crossed political boundaries. He was a cousin of John Manners, duke of Rutland, and brother-in-law to both the Tory peer Thomas Leigh, 2nd Baron Leigh, and the Exclusionist Sir James Oxenden‡.
Watson was probably one of ‘the lord Rockingham’s two sons’ to see service among the gentlemen volunteers with James Scott, duke of Monmouth, at the siege of Maastricht in 1673; their kinsman Captain Watson had the charge of Monmouth’s household.
Watson was disappointed in his efforts to secure a seat on this occasion and it was not until 1681 that he was returned to the Commons, where he served as member for Canterbury and, after the Revolution, for Higham Ferrers. He was also approached to represent Sandwich in 1689 and he offered to stand for that constituency at the next election.
Rockingham had still not received his writ of summons by 28 Oct. 1689 when he was excused at a call of the House. The writ was finally issued on 21 Nov. and he took his seat four days later. Thereafter he sat on approximately 56 per cent of all sitting days in the session. Though classed as an opponent of the court in a list prepared between October 1689 and February 1690 by Thomas Osborne, marquess of Carmarthen and later duke of Leeds, over the following six years Rockingham demonstrated little interest in the House’s business. Absent at the opening of the new Parliament on 20 Mar. 1690, he did not take his seat until 29 Apr. and was then present for much of May, attending a little under a half of the whole session. His attendance remained lacklustre during the following (1690–1) session. Having returned to the House two months into the new session on 1 Dec. 1690, he sat for the majority of that month, but his overall attendance accounted for only 19 sitting days in the session as a whole. Rockingham attended the single sitting day of 26 May 1691 but then failed to attend the 1691–2 session at all. He was present once more for the prorogation day of 24 May 1692, resuming his seat again almost three weeks into the following session on 21 Nov. 1692, after which he was present on approximately 20 per cent of all sitting days. On or about 31 Dec. 1692/1 Jan. 1693 he was forecast as a likely opponent of the divorce bill for the Whig peer Henry Howard, 7th duke of Norfolk, one of a group of Northamptonshire peers to rally to the support of the erring duchess, and on 2 Jan. he duly voted against it. The following day he voted in favour of passing the place bill.
Over the next two years Rockingham’s attendance at the House remained marginal. Absent at the opening of the new session on 7 Nov. 1693, he was excused at a call of the House on 14 Nov. and did not resume his seat until towards the end of the session on 9 Apr. 1694, after which he was present for just seven days (5 per cent of the whole). He then failed to attend the final (1694–5) session of the Parliament. He was again absent when the new Parliament opened in November 1695, only resuming his seat on 9 Dec., after which he was present on 14 days in the session as a whole (11 per cent of all sitting days). The death of Lady Rockingham in March 1696 may in part account for his absence from the House at that time. He covered his absence by a proxy in favour of John Holles, duke of Newcastle, registered on 9 Apr. and vacated by the close of the session. Rockingham resumed his seat at the opening of the new session of October 1696, after which he demonstrated renewed vigour, being present on 68 per cent of all sitting days. In December he voted in favour of attainting Sir John Fenwick‡.
Rockingham continued to attend with greater regularity during the following (1697–8) session. Having again taken his seat at the opening of the session on 3 Dec. 1697, he attended 64 per cent of sitting days. On 7 Mar. 1698 he was named one of the managers of the conference for amendments to the bill for explaining poor relief and on 15 Mar. he voted in favour of committing the bill to punish Charles Duncombe‡. The following day he entered his dissent at the resolution to grant relief to the appellants in the cause between James Bertie‡ and Lucius Henry Carey, 6th Viscount Falkland [S], and on 17 Mar. he dissented again from the resolution to allow the appellant to enjoy Carey’s estate for the life of Mrs Bertie.
Rockingham was named one of the managers of the conference for the bill of Peter Mews, bishop of Winchester, on 20 June 1698, and on 4 July he was named to the committee to inspect the Journals for 1640 and 1641 over proceedings against his grandfather, Thomas Wentworth, earl of Strafford. His level of attendance increased again in the ensuing Parliament: having taken his seat on 29 Nov. 1698, he was present on approximately 78 per cent of sitting days during the 1698–9 session. He attended the single sitting day of 1 June 1699 and resumed his place at the opening of the new session on 16 Nov., after which he was present on 60 per cent of all sitting days. In February 1700 he voted against adjourning during the debate for continuing the East India Company as a corporation and in July he was marked as a Junto supporter in a list differentiating between the various Whig peers.
Rockingham resumed his seat shortly after the opening of the first Parliament of 1701 on 10 February. Present on 74 per cent of all sitting days, in June he voted in favour of acquitting the impeached Whig lords, John Somers, Baron Somers, and Edward Russell, earl of Orford. During the election that winter, he approached Newcastle for his interest on behalf of his brother, Thomas Watson Wentworth‡, but without success.
He was present again at the opening of the next Parliament on 20 Oct. 1702 and he attended approximately two-thirds of all sitting days in the first (1702–3) session. On 17 Dec. Rockingham was one of those named to manage the conference over the bill to prevent occasional conformity; he was also named to the second conference on the same issue on 9 Jan. 1703. Estimated as being an opponent of the measure at the beginning of January 1703, on 16 Jan. he voted in favour of adhering to the Lords’ amendment to the penalty clause. Rockingham entered his protest on 19 Jan. at the resolution not to agree with the committee in omitting the clause for Prince George, of Denmark, duke of Cumberland, in the bill for settling a revenue on the prince in the event of the queen predeceasing him. Later that year, according to some sources, he was confirmed in the hereditary office of master of the buckhounds, an appointment that had eluded his father. There appears to be some ambiguity about this office, which may have been distinct from the identically named place in the royal household, which remained vacant at the time.
Rockingham resumed his seat shortly after the opening of the new session on 16 Nov. 1703, after which he was present on 61 per cent of all sitting days. In advance of the session he had been estimated as a likely opponent of the occasional conformity bill in two forecasts and in December he voted against the measure, though one division list gave his name, erroneously, as Buckingham rather than Rockingham. Later that month he was one of a number of Whig peers present at a conclave at the home of Charles Spencer, 3rd earl of Sunderland.
Rockingham resumed his seat on 11 Nov. 1704, after which he was again present on 61 per cent of sitting days in the session. In January 1705 it was reported that he had sent out his steward to make enquiries as to how the Northamptonshire freeholders stood affected for the forthcoming election.
An analysis of the peerage in or about 1705 listed Rockingham, predictably enough, as a supporter of the Hanoverian succession. On 2 Feb. he was named one of the managers of the conference to consider the heads of the conference to be held with the Commons concerning the Aylesbury men. He took his seat at the opening of the new Parliament on 25 Oct. 1705, after which he was present on almost 68 per cent of all sitting days in the first (1705–6) session. On 11 Mar. 1706 he was named one of the managers of two conferences concerning the letter of Sir Rowland Gwynne‡ to Thomas Grey, 2nd earl of Stamford, and of another on 13 Mar. concerning the militia bill. Despite his prominent role within Kent, Rockingham appears to have concentrated increasingly on his interest in Northamptonshire from 1705 onwards, attempting to bolster his position, along with Sunderland, as one of the principal Whig managers in the county.
Rockingham resumed his seat in the second session on 3 Dec. 1706, after which he was present on 63 per cent of all sitting days. He attended on six out of the ten days of the brief session of April 1707 and then resumed his seat on 23 Oct. at the opening of the new (1707–8) session, after which he was present on just over two-thirds of all sitting days. In April 1708 his heir, Edward Watson‡, married Lady Catherine Tufton, a match that further extended the family’s interest in Kent and brought with it a substantial portion, of £13,000.
Rockingham took his seat in the new Parliament on 16 Nov. 1708, after which he was present on just under three-quarters of all sitting days. In January 1709 he voted against permitting Scots peers with British titles from voting in the election for Scots representative peers. In April, Feversham’s death without heirs finally brought into Rockingham’s possession the remainder of the Sondes estates, along with an annual income of £3,000, which had been settled on Feversham by Rockingham’s father-in-law.
Present again at the opening of the new session on 15 Nov. 1709, Rockingham attended on just over two-thirds of all sitting days. Local interest was presumably behind his role in reporting from the committee for the Tonbridge road bill on 13 Mar. 1710. On 27 Mar. he was named one of the managers of the conference considering amendments to the act concerning the marriage settlements of Edward Southwell. The same month, he predictably found Henry Sacheverell guilty. In July, following the close of the session, rumours circulated, erroneously, that he was to be replaced as lord lieutenant by Heneage Finch, Baron Guernsey (later earl of Aylesford).
Rockingham took his seat two days into the new Parliament on 27 Nov. 1710, after which he was present on approximately 76 per cent of all sitting days during the first (1710–11) session. On 11 Jan. 1711 he registered his protest at the resolution to reject the petitions of the generals in command of the British forces at the disaster of Almanza. He also protested at the resolution to agree with the committee investigating whether the debacle at Alamanza was the result of the poor judgment exercised by the generals. Rockingham registered a third protest the following day in response to the resolution to censure the conduct of ministers for approving an offensive war in Spain. The following month saw him continuing to register his dissatisfaction with the manner in which the conduct of the war was being criticized by the new ministry, entering protests on 3 Feb. against the resolution to agree with the committee that the two regiments on the Spanish establishment at the time of the battle of Alamanza were not properly supplied and at the resolution that the failure of ministers to supply the deficiencies of men voted by Parliament amounted to a neglect of the service. On 8 Feb. he registered dissents both at the resolution to present to the queen the representation concerning the war with Spain and at the resolution to retain the words ‘and the profusion of vast sums of money given by Parliament’ within the address.
Rockingham appears to have anticipated being absent from the opening of the new (1711–12) session, as he registered his proxy in favour of Sunderland on 1 Dec. 1711, but this was vacated when he resumed his seat on the first day of the session on 7 December. In advance of the session, his name was included in a list compiled by Daniel Finch, 2nd earl of Nottingham, which may have been a further assessment of likely attitudes to the occasional conformity bill. On 8 Dec. Rockingham was also listed as a probable opponent of the court in an assessment of those opposed to presenting the address containing the ‘no peace without Spain’ motion. Present on just over 56 per cent of all sitting days that session, on 19 Dec. he was listed as opposed to permitting James Hamilton, 4th duke of Hamilton [S], to sit in the House as duke of Brandon; the following day he voted to prevent Scots peers from sitting in the House by virtue of British titles created after the Union. Rockingham was entrusted with the proxy of his neighbour George Nevill, 13th Baron Abergavenny, on 21 Dec., which was vacated on 7 Mar. 1712. He held Abergavenny’s proxy again from 19 Mar. to the close of the session. On 24 Mar. John Manners, 2nd duke of Rutland, also entrusted Rockingham with his proxy, which was vacated on 13 May. On 28 May Rockingham protested at the resolution not to address the queen requesting her to order an offensive war.
Rockingham was listed by Swift as a likely opponent of the ministry in or about March 1713. Having attended half a dozen prorogation days in between the close of the previous session and opening of the new one, he resumed his place on 9 Apr., after which he was present on 53 per cent of all sitting days. In June he was estimated by Oxford (as Harley had since become) to be opposed to the bill confirming the 8th and 9th articles of the French commercial treaty. During that summer, he was again involved with canvassing in Northamptonshire; his steward was reported to be ‘making interest for votes against the next election’, while Rockingham may himself have been responsible for proposing an alliance between his brother and Thomas Cartwright‡ in an attempt to foil the Tory effort.
He took his seat at the opening of the new Parliament on 16 Feb. 1714, after which he was present on 77 per cent of all sitting days during the first session. On 5 Apr. he acted as one of the tellers for the division on whether to agree to an address on the Protestant succession, which was carried by 14 votes. Rockingham was entrusted with the proxy of his Kentish neighbour Thomas Fane, 6th earl of Westmorland, on 19 Apr. (vacated 28 Apr.) and on 23 Apr. he also received Abergavenny’s proxy, vacated on 16 June. He was again entrusted with Westmorland’s proxy on 13 May (vacated by the prorogation on 9 July). On 27 May he was forecast as likely to oppose the schism bill and on 15 June he duly entered his protest at the resolution to pass the bill. On 8 July he entered a further protest at the resolution not to make a representation to the queen stating that the benefit of the Assiento contract had been obstructed by the efforts of some individuals to obtain personal advantages from the contract.
Rockingham’s interest within Kent was further consolidated by the marriage of his daughter Arabella to Sir Robert Furnese‡ in July 1714.
Rockingham died on 19 or 20 Mar. 1724. A rental of his estates in Northamptonshire, Huntingdon, Leicestershire, Lincolnshire, and Kent recorded his annual income to have been £4,114 15s. 8¼d.