Smith, 21, joins on a loan from English Championship side Queens Park Rangers through to the end of 2027 with an option to buy.
Olwethu Makhanya has recently joined Glasgow Rangers in Scotland after a successful few years at Philadelphia Union, while Mbekezeli Mbokazi has been an instant hit at Chicago Fire, though a serious thigh injury has knocked him out for the rest of 2026.
Smith has another similarity with Makhanya, both were part of the development set-up at Stellenbosch FC before heading overseas.
“Tylon Smith is a promising player who will help strengthen our defence,” Revolution General Manager and Chief Soccer Officer Chris Tierney said.
“At just 21 years old, Tylon has built a strong foundation through both his club and youth national team experience. We’re confident that this is the ideal environment for Tylon to continue his development and we look forward to welcoming him to New England.”
Smith was Player of the Tournament when South Africa lifted the Under-20 Africa Cup of Nations in 2025.
He is no stranger to Revolution coach Marko Mitrović, who was in charge of the United States side when South Africa beat them 2-1 at the FIFA Under-20 World Cup last year.