Mark Diamond has worked for the Australian Rail, Tram and Bus Industry Union (RTBU), first as its National Lawyer before ascending to serve as its National Secretary.

He is now a Senior Associate at Hall Payne, working in Sydney’s employment and industrial relations team. He is admitted to both the Supreme Court of NSW and the High Court of Australia.

During his career, Mark has had carriage of or been involved in hundreds of employment and industrial matters including, but not limited to, unfair dismissals, general protections, bullying & harassment, disciplinary processes, redundancies, underpayments, protected action ballots, suspensions of industrial action, disputes under enterprise agreements, union rule changes, and has run appeals as advocate before the Full Bench of Fair Work Commission.

Mark’s time at the RTBU was characterised by significant legal work as well as contributions to and leading the union's broader industrial activities, advocacy for workers' rights, and changes he pursued in the industries in which the RTBU operates.

Mark has previously served on various boards including the Jobs and Skills Council for the Transport and Logistics, a harm prevention charity for the rail industry, and the Australian Council of Trade Unions (ACTU) Executive.

Hear from Mark at Ethics 2025: What Not To Do