Born in Durban, Mpati grew up in the Eastern Cape, spending his childhood in Fort Beaufort and his adolescence in Grahamstown.
[1] However, during his infancy, his family moved to a farm in Fort Beaufort in the Eastern Cape, the hometown of his maternal grandparents.
[2] During his first year, in December 1968, he was arrested for illegally operating as a taxi driver, having borrowed his grandfather's car to make extra money transporting visitors from the local train station; he successfully defended himself in court, an experience that sparked his interest in law.
[1][4] He worked in his own chambers until March 1993,[1] when he took up the post of in-house counsel at the Grahamstown office of the Legal Resources Centre, a prominent human rights law organisation.
In that capacity, he chaired a high-profile 2009 disciplinary inquiry into the conduct of Western Cape Judge President John Hlophe.
Mpati retired from the judiciary in May 2016,[15] and Mandisa Maya succeeded him as Supreme Court President shortly thereafter.
[17] He led a three-member panel which also included Gill Marcus and Emmanuel Lediga and which opened its hearings in January 2019.
[18] In November 2022, he was appointed to lead an independent investigation into alleged misgovernance at the University of Cape Town during the tenure of vice-chancellor Mamokgethi Phakeng.
[1] In April 2013,[20] he was inaugurated as the chancellor of his alma mater, succeeding Jakes Gerwel, who had died in late 2012.