The Brisbane Broncos signed Newcastle recruitment manager Peter O'Sullivan for next season on a deal reportedly worth $2.5 million, prompting the Knights to secure coach Justin Holbrook through 2030.
Holbrook took charge after Newcastle finished with the wooden spoon in 2025, then led the club to the 2026 NRL grand final.
The Knights lost 19-18 to the Roosters, but reached their first grand final in 25 years.
Knights director of football Chris James said, "Justin has done an incredible job since arriving at the start of this season," praising the environment Holbrook created.
James said Holbrook had also reconnected the team with the Hunter community, and that extending his contract would help build on that bond.
Under Holbrook, captain and fullback Kalyn Ponga arguably had a career-best season, while Newcastle scored more tries from their own half than any other team.
O'Sullivan has helped oversee major changes at the Dolphins, Warriors and Roosters before joining the Knights, who became title contenders.
Reporter David Riccio called his departure "A significant, huge influence that is for any football club." Riccio said Newcastle would need to consider how to replace him.