The Ó Maol Phádraig surname is virtually extinct, yet the patrilineal descendants of Uí Mhaol Phádraig are unlikely to be so. Rather, it is considered those descendants most likely came to carry the surname Fitzpatrick or another Pátraic-surname form. The series of articles, ‘Ó Maol Phádraig, the name, the people, and the clans’, brings focus back to the lost surname. Part I explored the origins of the Irish given name Máel Pátraic, the patterns of its occurrence that are apparent in early annalistic records, and the connections to the regions of Éire where the name was commonly found. Part II (a) collated the records of Ó Maol Phádraig surname and Máel Pátraic given name occurrences in authoritative genealogies; (b) provided context and identified the clan-associated surnames among the population groups in which Máel Pátraic occurs, and; (c) reflected on the alignment of Máel Pátraic in genealogies and annalistic records, and the geographic spread the name, which may have led to the emergence of the Ó Maol Phádraig surname. Part III, explores the occurrences of the surname Ó Maol Phádraig in historical records from ca. 1550 to ca. 1700 AD, i.e., a good portion of the Early Modern period, which are numerous and most relate to Bréifne and Corcaigh. While Breifne records are richer and give a more structured picture of Ó Maol Phádraig lineages, including the existence of at least one Ó Maol Phádraig clann who had a ‘Chief of His Name’, Corcaigh records are more scattered across the region and mainly linked to key figures of the Desmond Rebellions and the Nine Years’ War. However, it is noteworthy that the surname Ó Maol Phádraig was recorded as early as 1306 in Corcaigh.