Gerald was admitted to the NSW Bar in 2008. He has since appeared in diverse jurisdictions, both at first instance and on appeal, ranging from the High Court of Australia to the Court of Arbitration for Sport, and in a diverse range of cases, including commercial, equity and insurance disputes, as well as constitutional and administrative law matters. These include two successful challenges to the constitutional validity of the National School Chaplaincy Program and a successful appeal in which the Commonwealth Government was held to have breached contractual obligations in failing to provide enlisted naval personnel with adequate apprenticeship training.

Before coming to the Bar, Gerald was an Associate to the Hon W M C Gummow AC, former Justice of the High Court of Australia, and then a solicitor at Mallesons Stephen Jaques (now King & Wood Mallesons).

Gerald was also previously a lecturer in Federal Constitutional Law at the University of New South Wales.

He is currently a member of the Review Tribunal of the NSW Branch of the Australian Labor Party.