Sir Bernard was the eldest son of Sir Bernard Brocas Senior. Although he is said to have been aged forty-one at his father's death in 1395, this must be a mistake for thirty-one. It is highly unlikely that he was the Bernard Brocas born to Sir Bernard’s wayward first wife, who, in reality, was the son of her subsequent husband, Henry Langfield. Bernard Junior was almost certainly the son of his father’s second marriage, in 1361, to Mary, daughter and heiress of Sir John des Roches (and widow of Sir John Boarhunt). He inherited her estates, along with the hereditary office of Master of the Royal Buckhounds, without dispute.

Bernard Junior grew up at the family estate of Clewer Brocas, but he would have spent much time at nearby Windsor Castle. Here, when in the country, his father was in constant attendance upon his close friend, the Black Prince; and Bernard was almost certainly amongst the playmates of the future King Richard II. Bernard married very young, to Joan, the daughter of Sir Thomas Middleton (although sometimes said to be the daughter of Gilbert Banbury of Holybourne), and the two may have lived largely at Beaurepaire in Sherborne St. John (Hampshire) while his father occupied Clewer, in order to be stay near the new King at Windsor. They had at least six children together.

By 1390, Bernard Junior had been knighted and entered the service of King Richard II. Tradition makes him carver to the Queen. He also acted as a feoffee for William Scrope, the Earl of Wiltshire, one of the King’s chief ministers. However, it is thought that he may not have been terribly diligent in his attendance at court, perhaps due to disapproval of some of King Richard’s actions. Surviving documents record him mostly in Hampshire and his name does not occur amongst Court records at the end of Richard’s reign. His father died in 1395 and Sir Bernard Junior inherited his wide-ranging estates, but Beaurepaire still remained his favourite and he was appointed JP for its county a year later.

Childhood friendships are, however, hard to break and Sir Bernard declared his wholehearted loyalty to King Richard not long after his deposition, for he was a key player in the Earl’s Revolt against the new monarch, Henry IV, in 1400. The King was informed of the plot, however, and the rebels fled west from Windsor in an attempt to gather support. Sir Bernard was taken, with many others, at Cirencester and sent to Oxford and then the Tower of London. He was tried, with three others, for treason by the young Earl of Arundel and condemned to death. He was executed on 5th February, being taken to Tyburn, where his companions only were hung and drawn, before all of them were beheaded. He was buried in the Franciscan Friary Church in London.

King Henry IV was not vindictive towards Sir Bernard’s family because of his father’s loyalty to his Henry’s grandfather, King Edward III. Indeed, he may have insisted on Brocas being spared the humiliation of hanging for the same reason. Lady Brocas was thus allowed to retain her dower and her husband's goods and their eldest son, William, was confirmed in possession of his father's estates by the end of the year.