A long-time friend of ULIO, Leo is a barrister at Greenway Chambers, specialising in industrial relations law. Leo has been recognised by Doyle's Guide as one of the leading employment law junior counsel in NSW since 2019, and in Australia since 2020. Amongst Leo's myriad of achievements across all areas of industrial relations are the significant wage increases secured for NSW school assistants, aged care workers, early childhood teachers, along with rail workers and firefighters in NSW (AM2020/99 Application to vary Aged Care Award – various decisions, concluding 2024, Re IEU [2021] FWCFB 2051, Combined Rail Unions v Sydney Trains [2023] FWCFB 52, Fire Brigade Employees' Union v Industrial Relations Secretary [2025] respectively).

Before coming to the Bar, Leo was the senior in-house lawyer and advocate for the Australian Manufacturing Workers Union, having started at the AMWU in 2006 and worked in and around the trade union movement ever since.