Correctional Services Minister Ronald Lamola has appointed Makgothi Samuel Thobakgale as acting national commissioner, his department said on Monday.
He replaces Arthur Fraser.
The public service department confirmed earlier this month that Fraser's contract would not be renewed, adding him to the latest in a long list of directors-general to vacate their positions.
Thobakgale joined the department just over a year ago as the chief deputy commissioner for incarceration and corrections.
Department spokesperson Chrispin Phiri described him as a "hard working, passionate, insightful and knowledgeable public servant".