[8] It was here that his lifelong enmity with Nicholas Nugent began: the two Irish law students were reprimanded for brawling by the benchers of the inn, and bound to keep the peace.
[citation needed] After years of lobbying for a senior judicial post, involving at least one trip to London, Dillon was, in 1577, made second justice of the Court of Common Pleas (Ireland),[13] serving under his great-uncle Sir Robert Dillon, chief justice of the Common Pleas.
[16] Nugent's execution in 1582 greatly damaged the reputation of a man who had always been unpopular, and caused the Queen and Lord Burghley to regard him with suspicion.
Meanwhile, Dillon was also willingly involved in the Elizabethan era religious persecution of the strictly illegal and underground Catholic Church in Ireland, even when it also meant harming his own relatives.
Although Dillon was not close to Sir John Perrot, FitzWilliam's successor as Lord Deputy, Perrot's downfall damaged his career as it led the crown to scrutinise closely the conduct of all senior Irish officials, thus giving an opportunity to Dillon's many enemies to come forward.
The case was strong: in particular, the charge that Dillon had wrongfully condemned William's uncle Nicholas Nugent, his predecessor as chief justice, to death for treason.
[21] Dillon had become very rich and there is no doubt that he used his wealth to placate influential members of the Privy Council with expensive gifts.
In addition, Elizabeth and Burghley, previously hostile to Dillon, had decided that a purge of senior Irish officials would simply deprive them of valuable public servants, however questionable their conduct, a view first put forward by Roger Wilbraham.
[citation needed] On 23 September 1594, the day of Chief Justice Weston's death, Sir Geoffrey Fenton wrote to Lord Burghley that Dillon was to be restored to the chief-justiceship.
[26] Elrington Ball remarks that while Dillon's conduct as a judge was deplorable, he was an eloquent public speaker, and a man of some personal charm and humour.