Bysse was born around 1602, the eldest son of Christopher Bysse (or Bisse), 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. He had a brother, Robert, and a sister Elinor (died 1680), who married William Ball, MP for
Kells from 1642 to 1649. Bysse was educated at
Trinity College Dublin. 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 (who was Recorder of
Drogheda, and died early in 1643) and his brother-in-law William Ball were among the leaders of the
royalist and Protestant faction in Parliament. This faction opposed the
royalist Catholic faction, but was 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 the
Protectorate Parliament as member for Dublin city, but was excluded from taking his seat. Although a sincere Royalist, he is said to have been of the faction (the "Kinglings") who were prepared to accept
Oliver Cromwell as King as a short-term solution. 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 (which was demolished in the 1760s), and also
Brackenstown near
Swords, County Dublin, which had been bought by his father around 1611. Later he was granted part of the freehold of Philipstown (now
Daingean),
County Offaly. The Bysse family also had an estate at Pelletstown, near
Castleknock. ==Personality and reputation==