Saint Frederick was trained in piety and sacred learning among the clergy of the Church of Utrecht. After being ordained a priest he was charged by Bishop Ricfried with the care of instructing converts. In 825 he was chosen to succeed him as bishop of Utrecht. Saint Frederick became involved in the difficulties between the sons of the emperor, Louis the Debonair, and their father and step-mother. During these disturbances the party of the young princes charged the Empress Judith with numerous immoralities. Saint Frederick admonished her of them which drew upon himself the fury and resentment of the empress.

On July 18, 838 after Saint Frederick had celebrated Mass and was about to make his thanksgiving he was stabbed by two assassins. He died in a few minutes while reciting the verse of Psalm 144, "I will praise the Lord in the land of the living".

William of Malmesbury and others beleive that the assassins were employed by the Empress Judith who could not pardon the liberty he had taken to reprove her sins. Baronius and Mabillon think that they were sent by some of the inhabitants of Walcheren.

Feastday is July 18.