Appointed a senior counsel in 2003, Champion has practised as a barrister for more than 33 years across all aspects of criminal law. He was admitted into practice in 1976 and signed the Victorian Bar Roll in 1977.

Welcoming Champion's appointment, president of the Law Institute of Victoria Caroline Counsel said Champion is highly-regarded in the legal community and has been an effective acting DPP. The LIV and its criminal law section members have worked closely with Champion over the years, particularly when he was chair of the criminal bar between 2007 and 2010.