O'Mahoney, Katharine Aloysia O'Keeffe (1851–1908), editor, educator, and writer, was born in Co. Kilkenny, daughter of Patrick O'Keeffe (b. 1803) and his wife Rose (b. 1824; maiden name unknown). The O'Keeffes emigrated to Methuen, Massachusetts, USA, c.1851 when she was ten months old. They later settled in Lawrence, Massachusetts, where she spent her life. After her primary education with the Sisters of Notre Dame in St Mary's parish school, Katharine attended Lawrence High School, where she graduated at the top of her class in 1873. In 1875 she returned to the school to teach history, rhetoric, and elocution. She was the first Irish catholic to be appointed to the faculty. It is likely that she taught the American poet Robert Frost (1874–1963) who entered Lawrence High School in the autumn of 1888. During her years as a teacher, she became a popular lecturer on historical, Irish, and literary topics. From 1903 to 1916 she was a regular speaker in the city's lecture series supported by the White Fund. Her interest in public speaking led to her assembling and creating her anthology A Longfellow night: a short sketch of the poet's life with songs and recitations from his works for the use of catholic schools and catholic literary societies (1898).
She also wrote occasional poetry, including a dramatic entertainment titled ‘Moore's anniversary: a musical allegory’ for the Thomas Moore (qv) centenary that was presented in 1879 as a farewell to Old St Mary's church. The twenty-three stanzas of rhyming couplets begin with Moore, shift to a valedictory to St Mary's, and conclude with lines alluding to Moore's ‘The song of Fionnuala’, and linking confidently Ireland's future with the parish's: ‘And may Moore's true free countrymen then crown their poet's brow/Within St Mary's promised hall, a hundred years from now’. When the new parish hall opened, she wrote the lyrics to ‘Glad welcome to St Mary's Hall’. Her most ambitious parish project was Sketch of catholicity in Lawrence and vicinity (1882), a narrative of the history of St Mary's parish that focused on generations of its priests and teaching sisters. In his study of Lawrence, Immigrant city: Lawrence, Massachusetts 1845–1921 (1963), Donald B. Cole cited her as the example of Irish-American intellectual life in the city: ‘Katie O'Keeffe, however, best represented the intellectual advances of the Irish. Whether composing a eulogy for President James Garfield, giving a talk on Motley or Tennyson, or reciting poetry at various meetings, this Irish-born school teacher and newspaper woman reflected the busy, but hardly profound, mind of her fellow Irish immigrants in the city’ (Immigrant city, 58). She was less interested in the profound than in the patriotic and the pious.
O'Keeffe actively supported the Lawrence branch of the Land League, which was founded after the January 1880 visit by Charles Stewart Parnell (qv). She spoke in support of the Land League in her public lectures. That she was one of the three signatories to the branch's resolution of sympathy, passed after Garfield was shot, suggests the active role she played in that organisation.
In January 1880, when the catholics of Lawrence established the New England Catholic Herald (1880), O'Keeffe was elected to its board and served as its secretary. She was a correspondent for the Boston-based Sacred Heart Review, the owner and publisher of the Sunday Catholic Register, and an associate member of the New England Womens' Press Association. When the American Protective Association organised in Lawrence in the years after the depression of 1893, O'Keeffe's Sunday Register confronted their nativist and anti-catholic biases, and helped defeat their challenge to the Lawrence immigrant community in the 1894 city elections.
Perhaps it was the visit by John Boyle O'Reilly (qv) to Lawrence in January 1877, to give a lecture entitled ‘The great Irishmen of the present century’, that inspired her to develop her series of lectures on notable Irish and Irish-American women for the catholic summer school in New London, Connecticut in 1892. She later published the lectures in Famous Irishwomen (1907). The book of fifty-two sketches of Irish and Irish-American women begins with the disclaimer that the chapters are retellings, not original research. Her biographies of Irish women from St Brigit (qv) to Lady Wilde (qv) are less valuable than her studies of lesser known Irish-American women such as American revolutionary war heroine Molly (Scanlon) Pitcher, civil war soldier Bridget ‘Michigan Bridget’ Devens, who fought with Michigan's First Cavalry, and New Orleans philanthropist Margaret Gaffney Haughery (qv). Her appreciations of Eleanor Donnelly, Louise Imogen Guiney, and Katherine Conway demonstrate the vitality of contemporary Irish-American women's writing. Her Famous Irishwomen was a first compilation of Irish and Irish-American women's lives.
Since she always linked Irish nationalism to Roman catholicism, she was the obvious choice to lead the Ladies' Auxiliary of Division 8 of the Ancient Order of Hibernians when they were established in Lawrence in 1904. She was later elected to the Massachusetts Board of the LAAOH, where she served as secretary. She died suddenly on 2 January 1908 in Lawrence. She married (July 1895) widower Daniel J. O'Mahoney, the superintendent of streets in Lawrence; they had no children.