He was the son of Robert of Braybrooke, who had served as High Sheriff of Buckinghamshire, Bedfordshire, Northamptonshire and Rutland, as well as Master of the Great Wardrobe,[1] and had accumulated large amounts of land in Northamptonshire, Leicestershire, Bedfordshire, Buckinghamshire, and Essex, mainly by buying the mortgages of people who could not pay them back.
[citation needed] When Robert died in 1211, Henry followed his fathers path, succeeding him as High Sheriff of various counties and raising more money for the king from his shires; Roger of Wendover named him one of John's "evil counsellors".
In June 1213 John commissioned him to repair Northampton Castle, but in 1214 he was replaced as High Sheriff of Bedfordshire and Buckinghamshire, and by 1215 he had defected to the baronial faction.
After the Treaty of Lambeth Braybrooke submitted to John's young successor, Henry III, and had many of his lands restored.
Braybrooke returned 16 counts of disseisins; enraged, William de Bréauté, Falkes' brother, seized him, and the allegedly brutal treatment he received led to a siege of Bedford Castle by royal forces.