Boswell’s father, Dr Johnson’s biographer, envisaged a legal career for his eldest son, who gave evidence in boyhood of considerable physical courage and developed into a tall muscular man, equally at home in the hunting field and the library. By the time he was 25 he had, according to his sister, ‘in abilities risen superior to what was expected of him’. Shortly after his father’s death in May 1795 he went to Leipzig to study law, but his stay was brief, and after visits to Dresden and Berlin he was back in London by June 1796. His inheritance was a promising one and by 1801 his income from rents far exceeded that enjoyed by his father: in 1820 he put it at £8,000 per annum.
In July 1816 Boswell secured the seat at Westminster which had eluded his father by buying his return for Plympton on the Treby interest. He evidently regarded the Whigs as dangerous and irresponsible maniacs and gave general support to government, voting with them in ten of the 13 divisions of the period 1817-1820 for which full lists have been found, including those on the suspension of habeas corpus, 23 June 1817, state prosecutions in Scotland, 10 Feb., the domestic espionage system, 11 Feb. and 5 Mar. 1818, and Tierney’s censure motion, 18 May 1819. In his maiden speech, 10 Mar. 1817, he argued that the landholders of Scotland had no desire for parliamentary reform, and he spoke against Scottish burgh reform, 23 Mar. and 6 May 1819, though on the first occasion he professed willingness to support a measure to give their inhabitants control over municipal expenditure. He voted against the extension of the franchise at Penryn, 22 June 1819.
Boswell had no sympathy for the economical reform movement. He opposed the abolition of sinecures proposed in the report of the finance committee, 5 May 1817, when he contended that the influence of the crown, so far from increasing, was at its lowest ebb, being deprived of its ‘means of rewarding public services’. In the same spirit he objected to the abolition of the justices in eyre, 19 May, and spoke and voted against the civil services compensation bill, 6 and 10 June 1817. He also voted against government on the scope of the inquiry into bank forgeries, which he wished to be confined to Bank of England notes, 14 May 1818, and on the cash payments bill, 14 June 1819. Boswell supported Newport’s motions for inquiry into Scottish statutes fallen into desuetude, 20 May 1818 and 23 Mar. 1819, and on 31 Mar., as a personal contribution towards the clarification of Scottish statute law, obtained leave to introduce a bill to repeal two old Acts against duelling, which passed into law on 3 July 1819. He voted against Catholic relief, 9 May 1817.
Boswell developed a grudge against ministers and particularly Liverpool, evidently because when he was negotiating for a seat in 1818, ‘to the very last no answer could be given by Lord Liverpool to an independent man who’, in his own words, ‘conscientiously supported the administration with more persevering punctuality than any paid man in office’.
At the head of his yeomanry Boswell played an active and conspicuous role in the suppression of disaffection in Ayrshire in 1820, but his resentment against Liverpool was intensified by refusal of a request for recognition of his services, probably in the form of a baronetcy. This sense of grievance combined with a crisis in his financial affairs led him to vacate his seat early in 1821, but he obtained a baronetcy in the following summer through Sidmouth’s influence.
Scott thought that Boswell ‘had all his father Bozzy’s cleverness, good humour, and joviality, without one touch of his meaner qualities’: he was ‘a proud man, and, like his grandfather, thought that his father lowered himself by his deferential suit and service to Johnson’.