O'Leary, Liam (1910–92), writer, film director, and archivist, was born William O'Laoghaire on 25 September 1910, the son of Donnachadh O'Laoghaire, a teacher, and his wife, Alice (née Burke), of South Main Street, Youghal. He spent most of his childhood in Wexford, and was educated at the Christian Brothers’ school and St Peter's College, where his father taught Irish and French. O'Leary's interest in film was apparent even in his childhood, and while a student at UCD he co-founded the Dublin Little Theatre Guild (1934). He left UCD the following year to work as a clerk in the Department of Industry and Commerce, a position he retained for the next decade while pursuing his passion for film in a wide variety of projects. He was a founder member of the Irish Film Society (1936), served as film critic for the magazine Ireland Today, and acted in the film Foolsmate (1940). In 1937 his Irish translation of Hamlet was broadcast by Radio Éireann, with himself in the title role, and in 1945 he published Invitation to the film (the first book written on cinema in Ireland).
O'Leary worked briefly for the Abbey Theatre in 1946, but resigned a year later following disagreements with the managing director, Ernest Blythe (qv). He concentrated on a freelance film career, acting in the films Men against the sun (1953) and Stranger at my door (1950), both by Brendan J. Stafford (d. 1991). He embarked on directing when he was commissioned to produce a short film as part of Clann na Poblachta's election campaign. The resulting film, Our country (1948), on which Stafford and Seán MacBride (qv) also collaborated, was a powerful portrayal of poverty in Dublin slums, and had a controversial reception. O'Leary was subsequently appointed by MacBride to the new cultural relations committee in the Department of External Affairs, and he produced some short films for the Department of Education. His burgeoning directing career abruptly ended, however, when his next film, Portrait of Dublin (1950), was suppressed by the Fianna Fáil government on its return to power in 1951, who apparently regarded it as an indictment of social policy.
After this disappointment, O'Leary was involved in a number of films, acting in Stafford's Men against the sun (1952) and in the Gaiety and Abbey theatres, but he focused increasingly on his work as a film historian. In 1953 he moved to London, where he worked for the next fourteen years as acquisitions officer of the National Film Archive and produced another two books, The silent cinema (1965) and The spirit and the clay (1967). He then returned to Dublin to work in the film department of RTÉ, where he remained until his retirement in 1986. Widely respected for his cinematic expertise, O'Leary wrote on film for the Irish Times and published the authoritative work Rex Ingram: master of the silent cinema (1980, 2nd ed. 1993). He often worked in television, serving as advisor to the BBC and ITV, and advising on the Channel 4 series A seat among the stars: the cinema and Ireland. At the request of the Dublin Arts Festival he organised the exhibition ‘Cinema Ireland, 1895–1976’ at TCD (1976), a project which convinced him of the urgent need for a national film archive. His subsequent research amassed a large collection of film memorabilia, and in 1990 he staged another exhibition, ‘From the Liam O'Leary Archives’, at the NLI, Dublin, where his collection found a permanent home. He was the subject of a 1983 documentary entitled The cinema palace: Liam O'Leary, by Donald Taylor Black.
O'Leary lived in Sandycove, Dublin, and died 15 December 1992 in St Vincent's private hospital, Herbert Avenue, Dublin; he never married. His film archives and personal papers are held in the NLI.