The Honourable Chief Justice William Alstergren AO is the Chief Justice of the Federal Circuit and Family Court of Australia (Division 1) and the Chief Judge of the Federal Circuit and Family Court of Australia (Division 2).

His Honour was appointed as Chief Judge of the Federal Circuit Court of Australia and a Justice of the Family Court of Australia on 13 October 2017. On 15 December 2017, his Honour was appointed Deputy Chief Justice and on 10 December 2018 his Honour was appointed Chief Justice of the Family Court of Australia.

 On 1 September 2021 the Courts were renamed the Federal Circuit and Family Court of Australia (Division 1) and (Division 2) respectively. His Honour was also previously the administrative head of the Appeal Division of the Court.

After graduating from Melbourne University in Law (and completing an LLM), Chief Justice Alstergren undertook articles with Kenna Croxford & Co. From 1991 he practiced as a barrister in Melbourne and took silk in 2012. His Honour was regularly briefed in large and complex commercial, family, industrial, administrative law and tax trials and appeals in the Federal Court, Family Court and state superior courts.

His Honour is a former Chairman of the Victorian Bar. Immediately prior to coming to the Bench, His Honour was the President of the Australian Bar Association.

He was appointed an Officer of the Order of Australia in 2022 in recognition of his eminent service to the law, judiciary and sport.

His Honour is the Head of Jurisdiction for two national courts which include 126 judges, 120 registrars and 2000 staff in 17 permanent locations and over 30 regional locations across Australia.