Pigot was born in Kilworth, co. Cork, the only son from the second marriage of a notable Catholic physician who ‘preferred seclusion and an honourable competency to the more active and emolumentary life of a city’.
A supporter of reform, Pigott quickly came to the attention of Pierce Mahony, a leading Dublin solicitor, and Daniel O’Connell, who selected him as his junior counsel, and for whom he was thought to have penned several pseudonymous letters on the reform question. In 1832, he became legal adviser to the registration committee of the National Political Union, producing an influential guide to electoral registration.
An amiable personality with a well-rounded intellect, Pigot was one of a group of Liberal barristers named (by O’Connell) as a candidate for high legal office in September 1834, who described him as a young man ‘of great, very great legal knowledge’. He took silk the following year and, being regarded as politically moderate, was appointed as law adviser at Dublin Castle by the Whig administration in April 1835. In 1836 he helped O’Connell to establish the General Association and, after being returned unopposed as an ‘O’Connellite Liberal’ in the place of Nicholas Ball for Clonmel in February 1839, was appointed solicitor-general for Ireland.
Pigot first spoke in the Commons in March 1836 to defend the government’s efforts to suppress agrarian crime in Ireland, making ‘a most favourable impression’ as a debater. His voice was described as ‘remarkably expressive’ and displayed ‘a sort of musical voluptuousness in his rich and finely harmonized tones’, but while he was both ‘fluent and forcible in his language’ his oratory was regarded by some as ‘better suited to the bars of the courts than to the floor of Saint Stephen’s’.
In March 1840, Pigot successfully guided the amended bill to reform the Irish municipal corporations through the House, which received royal assent, 10 Aug. 1840.
He was returned unopposed for Clonmel in 1841, when he admitted that the relative balance of the parties in parliament had caused measures such as the Municipal Corporations Act to fall ‘far short of what was required’. Under the Whigs, Pigot had been widely regarded as ‘fairly “booked” for the bench’, but, with the fall of the Melbourne ministry he retired as attorney-general and returned to the Munster circuit, where ‘as an equity lawyer he had few equals and no superior’.
As law adviser to Dublin Corporation, Pigot was part of the ‘formidable array of legal knowledge and oratorical power’ marshalled in defence of O’Connell at his state trial in 1844.
As a judge Pigot earned a high reputation for ‘probity, for clearness of judgement … [and] for lucidity of statement’, and administered justice ‘with inflexible firmness and even severity where public interests required it’. He was viewed by Nationalists as ‘beyond the influence of [Dublin] Castle’ and therefore enjoyed the ‘utmost confidence’ of all classes. Though valued for his diligence, it was said that his ‘high conscientiousness’ and ‘earnest desire to do justice to every suitor’ often led him to investigate the details of a case ‘with unwearied assiduity’, so protracting the trials at which he presided ‘to what some considered an unreasonable length’.
Pigot was particularly concerned with the education question. He joined the senate of the Queen’s College in Ireland in 1850, sat on the commission of inquiry into the management of Maynooth College in 1853-4, and was appointed a commissioner of Irish national education in March 1861.