Keppie was already on contract until the end of the 2024 season and couldn't have negotiated with another club until November 1 next year, but elected to extend his time with the Sea Eagles until at least the end of the 2026 season.
Keppie, who is now 24 years of age, has played 59 games for the Sea Eagles since his debut in 2019, becoming a permanent part of the club's first grade side in recent times.
Injury kept him to 17 games under Des Hasler in 2022, with nine of those from the bench and the remainder in the starting side.
With Martin Taupau set to exit the club though, Keppie can expect more minutes to be thrown his way in 2023 with a big pre-season, and the extended contract is testament to that.
“Sean has certainly worked hard and is becoming a natural leader of our pack," Sea Eagles CEO Tony Mestrov in a club statement.
“His best years as a prop are still ahead of him, so we are very happy to have him here for the long term.
“Furthermore, Sean is highly respected for his genuine work in the community that has seen him been the club's nominee for the Ken Stephen Medal for the past two years.”