Already contracted for next season, the 23-year-old has signed on for an additional three years in a major boost for the Bunnies. The back-rower has been one of the form forwards in the NRL over the past three seasons after defecting from Bradford Bulls.
"I absolutely love playing for the South Sydney Rabbitohs and embrace everything the club stands for," Burgess said. "I'm loving the lifestyle here in Sydney and there is no other club that I would want to play for in the NRL."
He added: "My team-mates, the coaching staff, the board, the office staff and in particular, the members, have all made this club my home over the past three years, and to have my brothers and Mum here with me next year makes it even more special.
"I'm very happy to have my future secured and I'm looking forward to the rest of the 2012 season."
Burgess has made 42 appearances for the Rabbitohs to date and is a veteran of 13 Tests for England and Great Britain. He will be joined by his three brothers - Luke, George and Thomas - at Redfern next season.
Rabbitohs coach Michael Maguire says securing Burgess long term is a major coup for the club.
"It's a great thing for the club and the team that Sam has agreed to sign long term with us," Maguire said. "He's a world class player and displays strong leadership qualities every day which is important to us as a team.
"He's a big part of what we're building here at Souths and as we look to the future, he's the type of player you can build your team and club around.
"He's all about the club, all about the team, and he's a real strength for us."