In 1998, after completing side-bar professional training and admission examinations, he was admitted and enrolled in the then Transvaal Provincial Division as an attorney at law and in 2007 was enrolled further as such in the Eastern Cape Province.

He has previously practiced the law in the District, Regional and the High Courts as a private legal practitioner and later became Justice Centre Executive of the Legal Aid Board. He has a keen interest in civil litigation, the Constitutional and Administrative Law as well as Labor Law areas of the legal discipline.

He has served as the provincial head of the South African Human Rights Commission in the Eastern Cape.

Apart from legal practice, Mzi has worked in the academic sphere, firstly, for the University of Witwatersrand as a Ford Foundation research intern based at the Center for Legal Studies and, secondly, for the University of Fort Hare as a law lecturer, director of the University’s legal aid clinic and as the University’s Deputy Registrar. He also has worked for Transnet Pipelines, an operating division of the Transnet SOC Ltd, as the head of its company secretariat.

He has now joined the South African Medical Research Council as a General Counsel.