Campbell possessed, apart from his ancestral estate and parliamentary interest in Nairnshire, one of the best estates in Pembrokeshire, where he was host to the fashionable world at Stackpole Court; and in the right of his mother, a Pryse of Gogerddan, a mineral producing estate in Cardiganshire. In 1789 he was said to be worth ‘11 or 12 thousand pounds a year’. Like his father, he sat for Cardigan Boroughs unopposed, but at the instigation of Thomas Johnes rather than on the Gogerddan interest. He was thought to have views on Pembrokeshire at the next vacancy and also in 1793 on Carmarthenshire, but was promoted to the peerage before the question arose.
Although he had been expected to go into opposition to Pitt’s government at its outset, he did not do so until his connexion with and marriage to the daughter of Lord Carlisle caused him to join the Whigs during the Regency crisis, 1788-9. He resumed this line, 12 Apr. 1791, by voting for Grey’s Oczakov resolutions, and was listed favourable to repeal of the Test Act in Scotland the same month, but no further minority votes are known. Campbell went over to government with the Portland Whigs in support of war and on 15 Mar. 1794 Pitt had the satisfaction of listing ‘Mr Price [sic] Campbell’ among those who opposed Grey’s motion to require a bill of indemnity on the landing of Hessian troops, in the debate of the previous day. Campbell, who rarely spoke in the House, deprecated appeals to precedent and thought expediency justified the measure. His diaries for 1792, 1794, 1795 and 1796 show that he attended fairly regularly, but report only the subject of debate and division figures. They show that he frequented Lord Carlisle’s circle, in which he liked to change the subject of conversation from politics to sport. He recorded that he said ‘a few words’ on 26 Feb. 1794 and that on 9 Mar. he began considering arguments for his speech of 15 Mar.: on the day itself he wrote: ‘a very bad headache and nervous’. He regularly attended debates on the slave trade, favouring abolition like Lord Carlisle. He also made notes on debates on defence.
On 28 June and again on 22 Aug. 1794, Campbell applied to Pitt for an English peerage. He obtained it at the dissolution in 1796: his father-in-law had been puzzled, so he informed Pitt, that Campbell had ‘repeatedly failed’ to gain Pitt’s ear on this matter and renewed the pressure, pleading ‘the great consequence to his private affairs and for his preparations for the general election of a decision’.
In January 1797 Lord Cawdor, as he now was, distinguished himself at the head of the Castlemartin yeomanry in halting the French invaders of Pembrokeshire, outshining the lord lieutenant, Lord Milford, in his exertions.