Young has signed a two-year deal with the PNG Chiefs after visiting Port Moresby, CODE Sports reports.
A contract fallout led Canberra to withdraw its extension offer; Young is expected to stay in 2027 and join Willie Peters' team in 2028.
The deal is understood to be worth about $1 million a season after the NRL deemed an earlier offer below market value.
Young is PNG's first high-profile forward signing, joining backline recruits Jarome Luai, Alex Johnston, Brian To'o, Zac Lomax and Joseph Manu.
An Achilles injury in July ended his season and ruled him out of the World Cup, where he would have been a walk-in at left second row.
He is expected to return for the Raiders in Round 1 next year.
Stuart said to News Corp: "We bent over backwards to try and keep Hudson and it would have been unfair on the club if we had went any further,"