Ua Conchobair, Ruaidrí na Saide Buide (d. 1118), a son of Áed and overking of Connacht, belonged to a family line descended from Conchobar (qv) (d. 973) son of Tadc, of the Uí Briúin Aí dynasty. His father was Áed in Gaí Bernaig Ua Conchobair (qv) overking of Connacht, and his mother Caillech Caimgein, daughter of Ócán Ua Fallamain, who belonged to a minor lineage of Dál Cais. He had at least five half-brothers: Cathal (whose mother was Étaín, daughter of Ua hEgra), whom he himself slew in 1082, Tadc (slain 1062), Murchad Liathánach (slain 1070), Niall Odar (d. 1109), and Cú Chonnacht. He also had two sisters: Aíbenn (d. 1066), who married Tadc Ua Muirecáin king of Tethbae, and Dubchoblaig (d. 1088).
Ruaidrí, dubbed na Saide Buide (of the yellow bitch), first married into the ruling line of the Conmaicne, but later pursued two successive marriage alliances with Dál Cais. From these three recorded unions, he had at least three sons: his first wife, a daughter of Éicnechán Ua Cuinn, who belonged to Muinter Gillucáin of Conmaicne, was mother of his son Tadc; a daughter of Ua Conaing, a minor Dál Cais dynast, was mother of his son Domnall; and Mór, daughter of the powerful Tairdelbach Ua Briain (qv) (d. 1086), died in 1088 at (or shortly after) the birth of his son Tairdelbach Ua Conchobair (qv), future claimant to the high-kingship of Ireland. Ruaidrí had two other sons – Niall (d. 1093) and Conchobar (d. 1103) – and a daughter Mór, who married Diarmait Ua Briain (qv), and bore him two sons, Tairdelbach (qv) and Tadc Gláe.
Ruaidrí did not succeed his father directly when the latter was slain (1067) by Áed Ua Ruairc (qv), son of Art Uallach of the rival Uí Briúin Bréifne dynasty, who laid claim to suzerainty of the province for seven years. It seems that by 1073 Ruaidrí had emerged to successfully challenge Áed. Certainly, the regnal lists count his reign as overking of Connacht from this point; the annal-record, however, reflects a struggle for dominance within the province for some years afterwards. In 1073 his future father-in-law Tairdelbach Ua Briain, striving to assert his own claims to high-kingship, intervened in Connacht and took hostages from both protagonists. Three years later Ruaidrí was taken prisoner by Ua Briain and released only when he tendered submission and agreed on a stipend.
Ruaidrí gradually consolidated his position under Dál Cais lordship. Political rivalry within the family provides the background for the battle in 1082 in which he slew his half-brother Cathal, who had treacherously killed their nephew, Domnall son of Tadc. In 1087 Ruaidrí moved against Uí Briúin Bréifne after that dynasty had been weakened by conflict with Ua Briain; he defeated and slew Áed Ua Ruairc at the battle of Conachail (near Achonry, Co. Sligo). By this time, the death of the powerful Tairdelbach had created room for political manoeuvre, as the latter's son and successor Muirchertach Ua Briain (qv) strove to re-establish the authority of his dynasty. In 1088 Ruaidrí submitted to Domnall Ua Lochlainn (qv) of the Northern Uí Néill, the latest claimant to the high-kingship, and joined him in an invasion of Munster, burning Limerick and destroying several Ua Briain fortresses, including Cenn Corad (Kincora). Subsequently, he blocked an attempt by Ua Briain to launch a naval attack on Connacht via the Shannon, obliging him to seek terms by 1090.
Shortly afterwards, however, political dissensions resurfaced in Connacht; according to some accounts, Ruaidrí was responsible for the drowning in 1092 of the cleric Fiachra Ua Fallamain – perhaps a kinsman of his mother. Before that year ended, he was blinded and deposed by Ua Flaithbertaig, king of western Connacht. The regnal lists claim that he was followed as suzerain by his son Tadc, but the annal record shows a fragmented kingship as his nephew Áed son of Cathal and rulers of neighbouring dynasties – notably Ua Ruairc of Bréifne and Ua hEidin of south Connacht – all staked claims to provincial rule, while their overlord Muirchertach Ua Briain exploited these rivalries to his own advantage. His son Tadc died in 1097, and was succeeded by another son, Domnall, as nominal ruler, till the latter was replaced (1106) by his 18-year-old brother Tairdelbach Ua Conchobair, who in time brought the dynasty to new heights. Ruaidrí died in penitence at Clonmacnoise in 1118, the same year as his son Domnall.