Sebastian De Brennan


Phone: (+612) 9224 5600

Mobile: 0410 343 720

Email:  s.debrennan@humanrightslaw.com.au or debrennan@7gbc.com.au

After a decade working as a solicitor, including running his own law firm in the Sydney CBD for five years (De Brennan Tomlinson Pearce or DTP Lawyers), Sebastian was admitted as a barrister in 2017. Although Sebastian will take on matters in many areas of the law, he has a particular interest in Criminal, Employment, Human Rights, Family Law and First Nations/Indigenous Law. 


Sebastian practises from Garfield Barwick Chambers in Sydney, however is also an interstate member of the Northern Territory Bar Association and the South Australian Bar Association. He regularly accepts briefs in regional and remote areas, as well as interstate, including those at short notice.

Outside of legal practice, Sebastian has been a Practitioner in Residence at the Centre for Excellence in Policing and Security (CEPS) and has taught the subjects Business Law, Prisons and Punishment and Criminal Law & Procedure at various universities. As well as holding degrees in business and law (with First Class Honours), he is a graduate of the Sydney Leadership Program and the Asialink Program at the University of Melbourne. He has also completed a Masters in Law at the University of Cambridge.


B Com LLB (Hons) LLM Grad Dip Legal Practice

Admissions: N.S.W., N.T., S.A., High Court of Australia

Select cases

Some high profile matters Sebastian has been involved in - as solicitor, solicitor advocate or counsel - include:

'R v SZ’ case, where client was acquitted in the Supreme Court of NSW in relation to his involvement in an outlaw motorcycle gang murder: https://www.theaustralian.com.au/news/latest-news/two-more-men-charged-over-shooting-death/news-story/bc3ca09b73d71b83b35207ffc3b23c17?sv=8cf910f5d56473eed6c524ffdabea066

‘Croatian 6’ case (2012) (NSW Supreme Court conviction review) involving six Croatian-Australian citizens who argued that they were wrongfully convicted of conspiring to bomb various Sydney targets: https://www.smh.com.au/national/nsw/terror-six-claim-it-was-fix-20120211-1sy8b.html

Lawyer for the family in Roberto Laudiso Curti Coronial Inquest (2012), involving the Brazilian student who died while being arrested and ‘Tasered’ at the hands of the police: https://www.smh.com.au/national/nsw/tasered-students-agony-shown-20121008-278zk.html

Soldiers’ Death in Afghanistan matter: Inquest into the deaths of James Thomas Martin, Robert Hugh Frederick Poate, Stjepan Rick Milosevic (2015)  Brisbane Coroner’s Court (solicitor for family of Private Poate): https://www.facebook.com/photo.php?fbid=10153078872956003&set=o.245781172280553&type=3&theatre

Solicitor for acting police officer in Operation Prospect conducted by NSW Ombudsman (private, four year, investigation examining complaints and allegations about conduct of officers of the NSW Police Force, the NSW Crime  Commission and the Police Integrity Commission) (2012 - 2016): http://www.abc.net.au/news/2016-12-20/senior-nsw-police-in-frame-as-operation-prospect-released/8135294

Lawyer for Connor McLeod and Vision Australia in their discrimination complaint against the Reserve Bank of Australia for not

incorporating tactile features on Australian banknotes (to assist those with vision impairment) - Australian Human Rights

Commission. See: http://www.smh.com.au/money/new-tactile-bank-notes-let-blind-people-get-a-feel-for-money-20160827-gr2r7r.html

BQJ v Children’s Guardian [2015] NSWCATAD 217  (as Solicitor Advocate) – murder/manslaughter offence against child – working with children check clearance – application for administrative review - Children & Guardian decision successfully set aside – working with children check clearance granted. Crown appeal to Supreme Court successfully resisted (led by Matthew Johnson SC): Children's Guardian v BQJ NSWSC  869

Collins v CE. Dept for Education and Child Development [2017] SATAB 3 - successfully argued that applicant had jurisdiction to bring claim – judicial review by Crown – matter referred to Full Court of Supreme Court of South Australia due to issues of public importance. Crown appeal to Full Court successfully resisted: State of South Australia v Collins [2018] SASCFC 110 (led by Brian Hayes QC). 


NSW Bar Association, Human Rights Committee (2018-2020)

CDPP External Junior Counsel Panel (2017-2021)

Member of the Legal Aid NSW summary crime panel, indictable criminal panel and duty lawyer scheme

Legal Services Commission General Panel (Counsel), S.A. (2017)

Sessional Lecturer & Tutor, Thomas More Law School, Australian Catholic University (2018)

Sessional Lecturer & Tutor, Western Sydney University, Dual appointment, School of Law & School of Criminology (2018)

Australia-Papua New Guinea Emerging Leaders Dialogue (2016), Lowy Institute for International Policy & DFAT.
Human Rights Committee, Law Society of NSW (2009, 2016)
Criminal Law Committee, Law Society of NSW (2010-2016)
Visiting Fellow (Practitioner in Residence) at the Australian Research Council Centre for Excellence in Policing & Security (CEPS) (2011).


Cambridge University Law Society (Life Member)
New South Wales Bar Association
South Australian Bar Association

Northern Territory Bar Association
Justice Net (SA)

© 2017 Sebastian De Brennan. Barrister at Law