Bysse was born around 1602, the eldest son of Christopher Bysse, who died before 1615. Christopher was an official of the Exchequer, as was his own father, Robert Bysse. John's mother was Margaret Forster, daughter of John Forster, an alderman of Dublin. Bysse was admitted as a member of the King's Inns in 1632. He was elected to the Irish House of Commons as member for Charlemont in 1634 and became Recorder of Dublin in the same year. He was re-elected to the Commons in 1640. At the outbreak of Irish Rebellion of 1641 John Bysse, along with his younger brother Robert were among the leaders of the royalist and Protestant faction in Parliament. This faction opposed the royalist Catholic faction, but were allied with it from 1649 to oppose the Cromwellian conquest of Ireland. During the Commonwealth he remained Recorder of Dublin, he was twice recommended for appointment to the High Court Bench and was elected to Parliament, but excluded from taking his seat. At the Restoration he was appointed Chief Baron of the Irish Exchequer and held that office until his death. In addition to serving on the Bench, he attended regularly at the Irish House of Lords, acting as a legal adviser to the Lords. He is buried in St. Audoen's Church, Dublin. Bysse became a substantial landowner, inheriting Preston's Inn, on the site of the present City Hall, Dublin, where he built a large mansion, and also Brackenstown near Swords, which had been bought by his father around 1611. Later he was granted part of the freehold of Philipstown, County Offaly.
Personality and reputation
Elrington Ball remarks flippantly that Bysse had a kind of "hereditary claim" on the Exchequer as both his father and grandfather had been officials there. In fact the author makes it clear that Bysse was eminently qualified to be Chief Baron: he had been Recorder of Dublin for 25 years and had sat in two Parliaments; he was hard-working, conscientious and popular with all political factions. In religion he seems to have been tolerant by the standards of the time, causing something of a stir in 1665 when he acted as mourner at the funeral of a nonconformist clergyman. Despite Bysse's undoubted good qualities, within a few years of his appointment as Chief Baron serious complaints were being made about his slowness and incompetence; he was even accused of senility. These complaints were taken seriously and in 1669 and 1671 he was threatened with removal from office. He was fortunate in enjoying the friendship of the Lord Lieutenant, James, Duke of Ormonde, to whom loyalty was a cardinal virtue: as Ball remarks "those whom he ever loved, he loved to the end". Ormonde strongly defended Bysse, admitting he was slow in giving judgement but arguing that his integrity and capacity for hard work compensated for this, and he denied that there had been any fall-off in Bysse's mental abilities. These arguments were presumably successful since he was not removed from office. In his last years there were persistent rumours that he would either resign or be dismissed, but in fact he remained Chief Baron until his death in 1680, aged about seventy-eight.
Family
John Bysse married Margaret Edgeworth daughter of Francis Edgeworth of County Longford, who held office as Clerk of the Crown and Hanaper from 1606 to c.1620. Francis was the brother and heir of Edward Edgeworth, Bishop of Down and Connor, and ancestor of the celebrated novelist Maria Edgeworth. Margaret was the widow of John King who was Clerk of the Crown jointly with his father-in-law. John and Margaret had numerous children who died young, and two surviving daughters:
