The veteran lock forward takes over from former head coach Johan Ackermann as the man in charge of the forwards.
Swys de Bruin has already been named as the union’s new head coach.
“I welcome another Springbok into the Lions family,” said union CEO Rudolf Straeuli on Thursday.
He comes into the mix having won the Currie Cup three times, the Super Rugby title three times, the Tri-Nations twice and the World Cup once.
“I love the culture of the Lions and felt I wanted to be a part of it,” Matfield said on Thursday.
“I also played under Swys while at Griquas (around 2000) and became a Springbok while under his tutorship,” said the 41 year-old said.
De Bruin’s new attack coach is former defence guru, JP Ferreira, while Joey Mangalo is the team’s new defence coach.
Ivan van Rooyen remains the conditioning coach and Rob Collins the team doctor.
The Lions, who’re one from three so far in the Currie Cup competition, face the Sharks at Ellis Park this weekend.