John Harris Byrne AO RFD KC (born 16 October 1948) is a retired Australian jurist who previously served as Senior Judge Administrator of the Supreme Court of Queensland.

Byrne commenced his legal career as an articled clerk for Morris Fletcher and Cross before being admitted as a barrister of the Supreme Court of Queensland in 1972.

The Legal Services Commissioner contended that the legal practitioner acting for a Plaintiff in a personal injuries claim had committed professional misconduct by failing to disclose the fact that his client had been diagnosed with cancer and then relying on a report in a mediation which had assumed a normal life expectancy for the client.

[3] In this case, Julie Gilfoyle, Burchill & Horsey Lawyers, Mylton Burns and McInnes Wilson Lawyers brought an application under the Vexatious Proceedings Act 2005 against the respondent Milton Arnoldo Conde, who had commenced more than two dozen proceedings in Queensland Courts between May 2009 and February 2010, including against solicitors and barristers acting against those he was suing, an Anti-Discrimination Tribunal member named Peter Roney and even the Chief Justice of Queensland Paul de Jersey.

The prosecution sought to change its manslaughter case to one of unlawful killing based on the surgery having caused the death of the patient in a way not justified or excused by law.

[10] If those submissions had been accepted, three of the four charges against Patel would have been doomed to failure, as criminal negligence committed during the relevant surgeries could not be established.

Justice Byrne held that the prosecution could not advance their new case because the fact that the surgery was consented to made it lawful, subject to s288.

[13] The Court also wrote that "The prejudicial effect on the jury was not overcome by the directions given by the trial judge about the limited use that could be made of that evidence".

In 2012, Justice Byrne presided over the trial of Massimo Sica, charged with having committed a triple murder in Bridgeman Downs in 2003.

Justice Byrne rejected the arguments that the alleged confession was not voluntarily given and that Sica was too intoxicated for the evidence to be admitted, and dismissed the application.

[19][user-generated source] On 8 December 2015, his conviction was downgraded to manslaughter by the Queensland Court of Appeal[20][21][22] on the ground that the evidence at trial was not able to exclude a reasonable hypothesis that "there was a physical confrontation between [Baden-Clay] and his wife in which he delivered a blow which killed her (for example, by the effects of a fall hitting her head against a hard surface) without intending to cause serious harm".

[20][24] According to his website, Byrne now works privately in dispute resolution, providing services in commercial arbitration, mediation, case assessment and referee determination.