Warenne was the son and heir of William de Warenne, 5th Earl of Surrey, and Maud Marshal.
His mother was the daughter of William Marshal, 1st Earl of Pembroke and widow of Hugh Bigod, 3rd Earl of Norfolk, making Roger Bigod, 4th Earl of Norfolk his elder half-brother.

A boy when his father died, Warenne became a royal ward.
Peter of Savoy was appointed guardian of his holdings and Warenne was raised at the royal court.
In 1247, he married Henry III's half-sister Alice le Brun de Lusignan, a marriage that created resentment amongst the English nobility, who did not like seeing a wealthy English nobleman marrying a penniless foreigner.

During the following years, Warenne was closely associated with the court faction centering on his in-laws.
In 1254, he accompanied the king's son Edward (the future Edward I) on Edward's journey to Spain to marry Eleanor of Castile.

During the conflicts between Henry III and his barons, Warenne started as a strong supporter of the king, switched to support for Simon de Montfort, and then returned to the royalist party.
He opposed the initial baronial reform plan of May 1258, but along with other opponents capitulated and took the oath of the Provisions of Oxford.
Warenne was the son and heir of William de Warenne, 5th Earl of Surrey, and Maud Marshal. His mother was the daughter of William Marshal, 1st Earl of Pembroke and widow of Hugh Bigod, 3rd Earl of Norfolk, making Roger Bigod, 4th Earl of Norfolk his elder half-brother.
A boy when his father died, Warenne became a royal ward. Peter of Savoy was appointed guardian of his holdings and Warenne was raised at the royal court. In 1247, he married Henry III's half-sister Alice le Brun de Lusignan, a marriage that created resentment amongst the English nobility, who did not like seeing a wealthy English nobleman marrying a penniless foreigner.
During the following years, Warenne was closely associated with the court faction centering on his in-laws. In 1254, he accompanied the king's son Edward (the future Edward I) on Edward's journey to Spain to marry Eleanor of Castile.
During the conflicts between Henry III and his barons, Warenne started as a strong supporter of the king, switched to support for Simon de Montfort, and then returned to the royalist party. He opposed the initial baronial reform plan of May 1258, but along with other opponents capitulated and took the oath of the Provisions of Oxford.
John de Warenne, 6th Earl of Surrey