From 567 to the death of Sigbert II in 613, Neustria and Austrasia were almost constantly at odds, with Burgundy playing the peacemaker between them. These struggles reached their climax in the wars between Brunhilda and Fredegund, queens respectively of Austrasia and Neustria. Finally, in 613, a rebellion by the nobility against Brunhilda saw her betrayed and handed over to her nephew and foe of Neustria, Chlothar II. Chlothar then took control of the other two kingdoms and set up a united Frankish kingdom with its capital in Paris. It was during this period that the first majores domus or mayors of the palace appeared. These officials acted as mediators between king and people in each realm. The first Austrasian mayors were drawn from the Pippinid family, which was to experience a slow, but steady ascent until it eventually displaced the Merovingian on the throne.
In 623, the Austrasians asked Chlothar II for a king of their own and he appointed his son Dagobert I to rule over them with Pepin of Landen as regent. Dagobert's government in Austrasia was widely admired. In 629, he inherited Neustria and Burgundy. Austrasia was again neglected until, in 633, the people demanded the king's son as their own king again. Dagobert complied and sent his elder son Sigebert III to Austrasia. Sigebert is widely regarded by historians as the first roi fainéant or do-nothing king of the Merovingian dynasty. His court was dominated by the mayors. In 657, the mayor Grimoald the Elder succeeded in putting his son Childebert the Adopted on the throne, where he remained until 662. Thereafter, Austrasia was predominantly the kingdom of the Arnulfing mayors of the palace and their base of power. With the Battle of Tertry in 687, Pepin of Heristal defeated the Neustrian king Theuderic III and established his mayoralty over all the Frankish kingdoms. This was even regarded by contemporaries as the beginning of his "reign". It also signaled the dominance of Austrasia over Neustria which was to last until the end of the Merovingian era. In 718, Charles Martel, with Austrasian support in his war against Neustria, each struggling to unite Francia under their hegemony, appointed one Chlothar IV to rule in Austrasia. This was the last Frankish ruler who did not rule over all the Franks. In 719, Francia was united permanently under Austrasian hegemony.
Under the Carolingians and subsequently, Austrasia is sometimes used as a denominator for the east of their realm, the Carolingian Empire. It has been used as a synonym for East Francia, though this is somewhat inaccurate.