Fulk II was the eldest son of Fulk FitzWarin I, a great marcher lord whose chief residence was at Whittington Castle in Shropshire. Although, amongst his many manors, he also held Wantage in Berkshire. His father died in 1171, when he was just a boy, and, as a ward of the King, tradition says he was brought up in the Royal household at Windsor Castle. As a child, the future King John was his playmate. However, the two fell out at an early age whilst playing a game of chess. John was losing, so in fit of peak, overturned the chessboard and punched Fulk in the mouth. Fulk hit back and the prince fell backwards, banging his head and falling unconscious. Fulk feared he had killed the boy, but was soon able to help him back to his feet. Prince John immediately ran off to complain to his father, King Henry. But the King just told his son that he had probably deserved all he got and punished him for telling tales.

Fulk II married Hawisia, daughter and co-heiress of Josce de Dinan, and is traditionally stated to have made a claim upon Ludlow Castle, which was never allowed. The Shropshire Pipe Roll of 1177 shows that he had been amerced forty marks by King Henry II for forest trespass. About 1180, he successfully disputed the right of Shrewsbury Abbey to the advowson of Alberbury. Ten years later, he was fined £100 for his wife's share of an inheritance and, through her, probably acquired an interest in several Wiltshire manors. On 6th November 1194, he was named as attorney for his wife in a suit of mort d'ancestre on account of lands in the same county; and was fined ten marks to be excused transfretation to Normandy. In 1195, he is entered as owing forty marks for the castle of Whittington adjudged to him in the curia regis. The fine remained unliquidated in 1202. He died in 1197. The next year, his widow paid thirty marks that she might not be obliged to remarry. Her name constantly appears as a litigant down to 1226. Fulk had six sons, of whom the eldest was Fulk III.

Despite his death, Fulk II was given a subsequent career in the traditional 'Romance of Fulk FitzWarin', which should more properly be ascribed to his son and namesake. The earliest version of this French manuscript survives in the British Library as a pre-1320 transcription, evidently paraphrased from an earlier record written before the end of the 13th century in octosyllabic verses, some of which remain unaltered.

Fulk III, in the year ending Michaelmas 1200, was fined £100, with King John to have judgment concerning Whittington Castle and its appurtenances as his right, which had been adjudged to him by consideration of the curia regis. The King was bribed by Meurig of Powys to confirm the latter in the possession of Whittington, whereupon in 1201 Fulk, his brothers and friends rebelled. The traditional story of the rebellion is the subject of the above mentioned romance and goes something like this:

King John is said to have given away Fulk's inheritance so easily because he had never forgotten how he (or his father) had been the cause of such extreme humiliation as a child. Fulk therefore swore that he would not serve John any more and so became outlawed. With his brothers and a band of trusty followers, he lived in the Shropshire forests robbing John’s wagon trains and harassing his soldiers. They often fought with Meurig’s men and, living under the protection of the Prince of Wales, took back his castle. Fulk and his men later fled to France, became pirates in the Channel, rescued the daughter of the King of Orkney and saved the Duke of Carthage from a ferocious dragon!

Upon their return to England, Fulk and his men heard that King John was holding court at Windsor, so they made for Windsor Forest and waited for the King to go out hunting there. Hearing one day that the King was in the vicinity, FitzWarin put on the clothes of a charcoal burner and sat himself down by his fire in a forest clearing. Soon, the King and his huntsmen rode by and stopped to ask if he had seen any good deer. Fulk replied that a huge beast had indeed just run by and led them into the thicket, ostensibly to find it. Of course, his own men were waiting there and King John and the Royal party were soon surrounded.

All Fulk really wanted was a quiet life and he agreed to let the King go if he would only promise to be his friend. Of course, the duplicitous John agreed at once, yet returned to Windsor Castle and immediately sent out Sir James de Normandy with an armed force to capture FitzWarin. Fortunately, one of Fulk’s men had followed the King and was able to send a warning. The outlaws were ready for the King’s men and, after a fierce battle, overcame them. Fulk exchanged clothes and horses with Sir James, tied him up and rode off to present King John with his prisoner. Thinking this was Sir James with a captive FitzWarin, the King wished to kiss the knight before him. Fulk, however, claimed he must quickly return to the battle in the Forest and John even gave him a fresh horse to speed him on his way! Only when Sir James’ helmet was removed did the furious King John discover the truth.

John sent a major force out into the Forest to hunt FitzWarin down and destroy his band of men once and for all. Despite a warning from his old friend, the Earl of Chester, Fulk decided to stand and fight. The battle was bloody and many of Fulk’s followers were killed. He himself was wounded, but his brother, John, managed to scoop him up onto his horse and they raced for the coast. The Earl of Chester hid another wounded brother, William, by placing him in a nearby monastery – Hurley perhaps – to recover, but he was soon discovered by the King and thrown into the dungeons at Windsor.

Fulk FitzWarin did escape, to Spain and then to the Barbary Coast in Africa. After further adventures, he returned to England to rescue his brother from prison in London. He eventually captured King John again whilst hunting in the New Forest and the two finally made peace. Fulk's outlawry was revoked by patent, dated from Rouen, on 11th November 1203 and, the following year, John restored Whittington Castle to him.