The 30-year-old made his official PSL debut against Jomo Cosmos back in 2007, and due to long-term injuries and suspensions among other factors, it took him just over a decade to reach the milestone.
He joins Siphiwe Tshabalala, who reached and surpassed the 300 mark for the Soweto giants in 2017,
Reacting to the milestone, Khune admitted that his body strength is regressing, but he feels wiser, and he declared his hunger for more success at the club.
"With age, my body strength is slowly regressing, but I am able to read situations much faster and, as a result, close down situations before they become dangerous," Khune told the Amakhosi website,
"Goalkeeping is like good wine, the older the better. I am still hungry for more success and want to win more trophies," he said.
Apart from Khune, who has already cemented his legendary status at the Naturena-based outfit, players such as Neil Tovey, Doctor Khumalo, Brian Baloyi and Thabo Mooki among others, also featured 300 times for the club.
Khumalo still holds the record for most appearances (397) at Chiefs, and at this rate, Khune appears likely to break that record in the next few years.
The Klerksdorp-born shot-stopper is also the most capped goalkeeper for Bafana Bafana (86) since South Africa's re-admission to the international stage in 1992.
He has kept a whopping 15 cleansheets for the Glamour Boys so far this season, and with six league games and possibly three more Nedbank Cup matches still to play depending on how far Chiefs can go, Khune could beat his record number of cleansheets (17) set during the 2013/14 season.