He and his first cousin, Donnchad, were co-Kings after Torloch's uncle, Brian, died, from 1277 - 1284. After Donnchad died, Torlogh was sole King until 1306.

From Chart of Hon Donough O'Brien, "The Viscounts Clare" Branch of the "O'Brien" Family:
Either he or his father, built Castle of Clonroad.

In 1304 Turlough O'Brien, the son of Teige Caelius, made an attack on Leathrach Odhrain, and burnt that town, then inhabited by the English, and slew the Englishmen dwelling therein. From the Annals of Inisfallen.14

Turlogh O'Brien, King of Thomond, or North Munster, attacked Latteragh in 1304; he slew all the Englishmen in Latteragh, but he spared all the churches and the dwellings of the clergy.14

Brian Rua the deposed King of Thomond, appealed to de Clare to help him regain his throne. In return for his support Brian Rua promised that he would allow de Clare to colonise all the land between Athsollus (in Quin) and Limerick. Brian Rua and his Norman ally Thomas de Clare, with a strong force, expelled Toirdealbach O'Briain and recaptured Clonroad. Toirdealbach fled to Galway and elicited support from his Norman cousin William de Burgh; together with assistance from the McNamara and O'Dea clans they defeated the combined forces of Brian Rua and Thomas de Clare 1277. King Brian Rua fled to Bunratty castle and there Thomas de Clare had him treacherously hanged and drawn.

The civil war between the O'Briens continued for some more years with de Burgh supporting Toirdealbach, while de Clare had become reconciled to Donogh, son of King Brian Rua, and assisted him. The bitter family feud ended temporarily in 1280 when de Clare attempted to impose a settlement by partitioning Thomond. Toirdealbach was to rule in East Thomond while Donogh was to reign in West Thomond. Toirdealbach, however, did not welcome the idea of ruling half a kingdom and hostilities resumed until Donogh was drowned during a party at Island Magrath on the Fergus near Clare Castle in 1284. From that date until his death in 1306 Toirdealbach ruled as undisputed King of Thomond. De Clare had no choice but to reach an accommodation with him and Toirdealbach rented part of the Bunratty manor at a rent of £121 p.a.
Meanwhile, in 1280, Thomas de Clare embarked upon a major castle-building project at Quin but this was destroyed by the McNamaras in 1285. Thomas de Clare died in 1287 leaving behind him a thriving Norman manor and stronghold at Bunratty castle. At the time of his death his sons Gilbert and Richard were minors. The minority of the de Clare's was a factor which aided Toirdealbach to rule without strong Norman opposition.