The Lions of the North offered Shongwe a six-month deal with an option to renew for a further year at the end of June 2019.
Shongwe is a well-travelled midfielder whose career has taken a nosedive since leaving the Brazilians over three seasons ago.
The 28-year-old has already joined his new teammates at the training grounds as Highlands Park prepare to take on Kaizer Chiefs in Durban on Saturday night.
It is unclear if the left-footed player will be available for selection when his team battle against Amakhosi at the Moses Mabhida Stadium.
Shongwe joins Owen Da Gama's side just a few days after former Amakhosi and Bafana Bafana winger Mandla Masango was turned down.
Masango had been training with the Tembisa-based outfit in an attempt to revive his fading career, but he didn't do enough to convince the technical team that he deserved another chance.
Both Masango and Shongwe featured for Bafana Bafana in the past, and with the latter having been given a second chance to redeem himself, it remains to be seen if any of the PSL teams will show interest in the former Chiefs man.
Highlands Park are currently placed ninth on the PSL log with nine league games to go.
They have collected 26 points from 21 league matches thus far, and a win over Amakhosi could see them move level on points with Ernst Middendorp's side.