About Mark O'Brien

Career

From Sydney University to his own firm.

Mark Geoffrey O'Brien studied Arts and Law at the University of Sydney and was admitted as a lawyer in New South Wales in 1970.

Over more than four decades he headed the litigation group in several national Australian law firms, including Gilbert + Tobin, before moving to Johnson Winter & Slattery in 2006. He has supervised major litigation in the Federal Court and the Supreme Courts of Australia and has worked with leading US, UK and European law firms.

In July 2014 Mark founded Mark O'Brien Legal in Sydney, a firm focused on media, defamation and reputation management, alongside commercial disputes, corporate governance and corporate crime and investigations.

Notable matters

As described on the Mark O'Brien Legal website, Mark's work has included:

• Acting for a billionaire falsely accused of bribing a President of the UN General Assembly
• Acting for an international cricketer falsely accused of indecent exposure in a team dressing room
• Successfully representing a former senior Australian politician in defamation proceedings against mass media
• Acting for Publishing and Broadcasting Limited and the Australian Rugby League in the Super League dispute with News Limited
• Acting for the Seven Network against Network Ten to restrain a senior executive from joining a rival network
• Federal Court proceedings against Airservices Australia over the regulation of Australian airspace
• Representing government ministers at ICAC private and public hearings
• Acting with US attorneys in civil RICO proceedings in the US District Court
• Legal advice and commercial disputes for the Sydney Organising Committee for the Olympic Games