Adalhard (Adalhardus, Old French Adalard) was the grandson of Charles Martel through Martel's illegitimate son Bernard — placing him in the most intimate inner circle of the Carolingian dynasty. He was the first cousin of Charlemagne, the first cousin once removed of Louis the Pious, and the maternal uncle of Wala (his brother and successor at Corbie).
Educated at the Carolingian court school under Alcuin, he refused to participate in Charlemagne's repudiation of his Lombard wife Desiderata in 770 — withdrew in protest to the monastery of Corbie, becoming a monk. He became Abbot of Corbie around 780 and was for forty years the most learned of Carolingian abbots — Alcuin called him the 'Antony of the West'.
Charlemagne entrusted him with the governance of the Lombard kingdom — Adalhard served as the principal tutor and regent of Charlemagne's son Pippin of Italy (king of the Lombards 781–810). Under Louis the Pious, he was exiled to the monastery of Noirmoutier on the Atlantic coast (814–821) for political opposition; recalled by Louis in 821, he returned to Corbie and immediately undertook the mission to Saxony.
In 822 he founded — together with his brother Wala — the great daughter foundation of Corvey on the Weser (in conquered Saxony, in Westphalia), the Carolingian monastic centre of Saxon Christianity. The Carolingian westwork of Corvey, completed in 885, survives today as a UNESCO World Heritage site (inscribed 2014) — the oldest preserved Carolingian church architecture in Germany. Adalhard died at Corbie on January 2, 827, leaving Wala as his successor.