MacCarthy, John George (1829–92), MP and land commissioner, was the son of John MacCarthy, of Cork, merchant, and his wife, Jane, daughter of George O'Driscoll, of Cork, distiller. He was educated at St Vincent's Seminary in Cork. In 1845 he delivered the welcome address to the visiting Daniel O'Connell (qv), and he showed an early propensity for writing, contributing articles to the Dublin Review by the age of sixteen. After leaving school he helped found two Cork institutions: in 1849, with Justin McCarthy (qv), he established the Cork Historical Society and in 1852 he founded the Cork Young Men's Society. In 1851 he undertook a continental tour, the experiences of which gave him the material for his first publication, Letters on land tenures, in which he contrasted Irish and continental tenurial systems.
Having qualified as a solicitor in 1853, MacCarthy established a lucrative legal practice with his brother-in-law in Cork and became involved in municipal politics. He was made alderman in the late 1850s and later unsuccessfully contested the mayoralty against Sir John Arnott (qv). In 1859 he married Maria Josephine, daughter of John Hanrahan of Mount Prospect, Cork, merchant. From the late 1860s he began writing on the land question and home rule. He unsuccessfully contested the seat for Mallow in 1872 but won it in 1874 as a home ruler. At Westminster he devoted himself chiefly to the land question, in particular the extension of tenant right throughout Ireland and land reclamation, which he saw as beneficial for landlords, tenants, and labourers. Another passionate cause was higher education for catholics; he argued that protestants had a near monopoly on higher education, as there was a virtual exclusion of catholics at TCD and the Queen's colleges. Educationally, he saw catholics as a disadvantaged majority who still had to compete in life and for office with a privileged minority. For his promotion of catholic interests, he was made a knight of the order of St Gregory by Pope Leo XIII in February 1880.
Having retired from politics in 1880 to return to his legal practice, in 1882 MacCarthy was appointed one of four legal assistant commissioners for the land commission created by Gladstone's 1881 Land Act. The commission's purpose was to fix ‘fair’ or ‘judicial’ rents for tenant farmers for a fifteen-year period; in effect, most judicial rents were reduced rents. MacCarthy presided over the sub-commission of Mayo, Galway, and Kerry until the creation of the estate commission under the Ashbourne Act (1885). He was then appointed as one of two commissioners (with Stanislaus John Lynch (qv)) to oversee the financial facilities for tenant farmers to purchase their farms. He remained an estate commissioner until his death, on 7 September 1892 at the Euston Hotel, London, where he was staying on his way home from a continental trip to improve his health. He was buried at Glasnevin cemetery, Dublin.