John O'Donovan was born on July 9, 1809, at Attateemore, County Kilkenny, Ireland. His father was a farmer, and on his deathbead, repeated several times to his son their line of descent from a third century king of Munster.

O'Donovan received his education in both Kilkenny and Dublin and, despite the limited opportunities for Roman Catholics, he joined the Irish Record Office in 1826. He worked, mainly, on Irish manuscripts and legal documents.

In 1829 O'Donovan was appointed to the historical department of the Ordnance Survey of Ireland, initially working place names for maps, but later, working under George Petrie, collecting historical material for the proposed memoirs to accompany the maps. His letters were later edited by Father Michael O'Flanagan, and published as The John O'Donovan Archaeological Survey, in fifty volumes, from 1924 - 1932.

During his time at the historical department, O'Donovan was also writing for The Dublin Penny Journal and The Irish Penny Journal, and wrote a series of articles on Irish family names. In 1840 O'Donovan and Eugene O'Curry (his coworker and brother-in-law) helped to found the Irish Archaeological Society. He left the Ordnance Survey in 1842, when the project was down-sized.

O'Donovan was also busy translating many early Irish manuscripts and creating many original maps of ancient Ireland. In 1845 he wrote A Grammar of the Irish Language comparing medieval and modern modes of spoken and written Irish. Before his death O'Donovan wrote a supplement to Edward O'Reilly's Irish Dictionary.

Perhaps his greatest work was the translation of the Annals of the Four Masters. It was published in seven volumes between 1848 and 1851. The original text, in Irish, appeared on one page and the translation of the text in English appeared on the facing page. The type font for the Irish text was created by Petrie.

Because of O'Donovan's and O'Curry's work there was a resurgence of interest in learning Irish history and literature, providing a wealth of materials which inspired the writers and artists of the Celtic Revival. O'Curry went on to become a professor of archaeology and Irish history at Catholic University. O'Donovan went to study law at Gray's Inn, in London, and was admitted to the Irish Bar in 1847. In 1849 he became professor of Celtic languages at Queen's College, Belfast. In 1852 he joined the Brehon Law Commission, founded to publish the Seanchus Mor, or ancient laws of Ireland. Sadly, he did not live to complete this work. O'Donovan died of rheumatic fever in Dublin on December 9, 1861.


Sources:

Dictionary of National Biography
A Dictionary of Irish Biography
Where they lived in Dublin