Pangai Junior has made 147 NRL appearances and started at prop for the NSW Blues in the 2023 State of Origin under coach Brad Fittler.
His NRL clubs have included Brisbane Broncos, Penrith Panthers, Canterbury-Bankstown Bulldogs and the Dolphins, whom he joined after coming out of retirement.
He also played 23 matches for Catalans Dragons in 2025.
Leigh Leopards have signed the 30-year-old Tongan forward to a multi-year deal, with his move from Hull KR set for 2027.
Consecutive suspensions and several weeks out disrupted his 2026 Hull KR season.
Leigh coach Adrian Lam welcomed the signing as a step towards building a strong squad for 2027.
"Me and my family are very excited to join Leigh Leopard," Pangai Junior said in a Leigh statement.
"We're grateful as a club that these types of players want to come to us," Lam said.