Upon getting his Bachelor of Laws by UFMG (the Federal University of Minas Gerais) in 1988, Maurício Campos Júnior became a Public Defender for the Trial by Jury Criminal Court of Belo Horizonte (where he served until 2003) and has practiced criminal law in Belo Horizonte for the past 30 years. He has taught Criminal Procedure at the Catholic University of Minas Gerais for around 30 years and has also been a Federal Advisor of the Brazilian Bar Association.

Maurício Campos Júnior is often acknowledged as a widely admired lawyer in expert publications, besides writing expert articles and giving lectures at seminars all over Brazil.