An acquaintance with Enos Throop, United States chargé d'affaires at Naples, begun in December 1838, helped him in the study of English, and this knowledge gained him the post of legal adviser to the British legation at Naples, and the friendship of the minister, Sir William Temple, at whose table he met many English travellers of distinction.
He was an unsuccessful candidate for the representation of the city of Naples in 1848, and on 7 April was appointed secretary to the Neapolitan legation in London, but did not start for his post, which he resigned after the fall of the liberal Troya ministry in May.
[1] He was at Edinburgh on 14 February, in May he was an unsuccessful candidate for the office of librarian of the London Library, and on 15 June he married Maria Clavering (died 1853), daughter of Sir Thomas Gibson Carmichael, seventh baronet.
[1] Lacaita was entrusted by Cavour with a delicate diplomatic negotiation in 1860 connected with schemes to prevent Garibaldi from crossing from Sicily to Calabria, and subsequently the Neapolitan government offered him the post of minister in London with the title of marquis, both of which he declined.
In December 1860, after the expulsion of the Bourbons, he revisited Naples, caused his name to be reinstated on the municipal registry, and in July 1861, while back in England, was returned as deputy to the first Italian legislature.
[1] Though speaking but seldom in the chamber, he exercised a considerable influence upon public affairs between 1861 and 1876 through his intimacy with Ricasoli, La Marmora, Minghetti, Visconti-Venosta, and other leading men.
In 1884, the English writer Janet Ross and her husband travelled to Apulia where they stayed with Sir James Lacaita at his estate (Villa Leucàspide).