The 21-year-old has played 14 times for Usuthu this season as the club look to make a final push toward the top end in the last stretch of the season.
"I feel so happy and privileged for extending my contract with the club that took care of me, a club that gave me a platform when I first arrived in South Africa," Darpoh said on the club's website.
"It’s with great honour and pleasure that I have committed my future to this club, and I am very happy with this opportunity.
"It’s been a journey of hard work, coming from the youth structures of AmaZulu, being promoted to the senior side. It’s been a lot of hard work and dedication.
"AmaZulu is a very professional club and a great club to be with. I remember when I first played my first match for the club in the NFD. The feeling was great, and I thank God.
“I think I’ve improved year by year when I look back from the motivation I get from the coaches, management and teammates that regularly.
"I’m growing to becoming a better player. Hopefully with God’s favour, and lots of hard work I can become an asset to the club and even my country one day."