The Saints skipper came through the academy and has made 278 first-team appearances for the south-coast outfit.
“I have said before that Prowsey is a player who shows everything that Southampton Football Club is about," Hasenhuttl told the club's website.
“It is not only his story of being developed as a player here, but also the commitment and attitude he shows in his work. He was not playing so much when I arrived, but he has listened and worked on every aspect of his game, and that is why he has reached the level he is now at.
“He has a passion for the club that everybody knows about, and he is respected by everyone here. I know he is a role model for our younger players especially, and these are all reasons why he was the right choice to be a long-term captain of this team and this club.
“He deserves congratulations for this contract and this is very good news for our team and our club."
Need a VPN? Or seeking to switch? Then support Tribal Football by clicking here to sign up with our official partners NordVPN. Not only will you receive the best VPN experience, but also great discounts by signing up via Tribal Football. Thanks for your support!