The front counter service in Caerphilly, Chepstow, Maindee, Monmouth, Pontypool, Risca and Ystrad Mynach was closed or reduced in 2012.
They were initially reopened in 2014 and following a consultation, Mr Johnston says they will stay open.
"I'm delighted to announce that these stations will remain open," he said.
The stations will open on weekdays 09:00-17:00 GMT; in addition, Abertillery station will open on Thursday and Friday 09:00-17:00 and Brynmawr station will open Monday to Wednesday 09:00-17:00.
Seven police stations in the Gwent force area are to reopen permanently, the Police and Crime Commissioner Ian Johnston has said.