He was appointed count and margrave of several counties in the Marca Hispanica by Charles, possibly as early as 854 and no later than 858.
In 858, Humfrid negotiated a treaty of peace with Abd al-Rahman, the Moorish governor of Zaragoza, and marched into Gaul to the assistance of Charles.
In September, Humfrid regrouped with his forces at Beaune before joining in the defeat of Louis at Saint-Quentin on 15 January 859.
This was opposed by the nobles, who, with the exception of Humfrid, did not support the young Charles in his subsequent rebellion.
Even the pretender Pepin II of Aquitaine led a band of Norsemen in an attack on Toulouse, but was repulsed.