O'Hagan (née Osborne), Harriet (1830–1921), portrait painter, was born in Dublin and studied drawing with George Sharp RHA (1802–77). As Harriet Osborne, aged nineteen, she exhibited, for the first time with the RHA, a lithograph of Mrs Hone after Mr Burton. From an address at 195 Great Brunswick Street she entered four portraits in 1851, including one in chalk and a watercolour of the Young Irelander Richard d'Alton Williams (qv). Sharp encouraged her to go abroad and she spent a period of time in London, exhibiting with the RA (1854) as Mrs O'Hagan of 193 Stanhope Street, London. It is unclear when and where she married.
Eventually she went to Paris, when she was in her later thirties, about 1866, and studied with Thomas Couture (1815–79), Léon Cogniet (1794–1880), and J. N. Robert-Fleury (1797–1890). Couture ran classes for women at his estate, Villiers-Le-Bel, and it is likely that she wished to renew and extend her skills, for Couture was considered an excellent teacher, who stressed the importance of colour and gave solid training in technique. She gave classes herself and it is suggested that she opened an academy for women. In Paris between 1866 and 1876 she showed (mainly portraits) in the salon exhibitions; one, of her daughter, was entitled ‘Marguerite s'amuse’. Despite the fact that she was in Paris at about the same time as Sarah Purser (qv) and mixed with her circle, little has been recorded of her personal life or her career. Purser executed a portrait in pastel on canvas of Mademoiselle Lemercier about 1887 (private collection); it is very likely Marguerite Lemercier O'Hagan (1859–c.1930), the daughter of Harriet O'Hagan. There is a possibility that the portrait was executed in Ireland, perhaps on a visit.
The NGI was presented with two of her oil paintings and four charcoal drawings in 1948, by M. Garbaye and J. de L'Etre of Savigny-sur-Oise, France. Three of the charcoal drawings are portraits, one thought to be that of her sister Eugénie (undated), and the other two of her daughter Marguerite. Some sources suggest that both sitters are her sisters, but this is unlikely as one portrait is dated 1869, and the sitter said to be aged ten: the artist was born in 1830, which would make the age difference too great for sisters. Her drawing is skilful and the portraits are sensitively modelled. The fourth charcoal drawing is ‘Farm in Normandy’ (1880). The two oil paintings are titled ‘Maximilian O'Hagan’ and ‘Interior’. O'Hagan spent the rest of her life in France and is known to have regretted that she had been unable to return to Ireland. She died in Paris in 1921.