Burgess, 23, has played 42 NRL games and is one of the club’s co-captains, and the new deal will keep him at the club until the end of 2016.
He said: “I absolutely love playing for the South Sydney Rabbitohs and embrace everything the Club stands for.
“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 will be joined next season by brothers Luke, George and Tom, who completes the quartet by joining from Bradford.
Rabbitohs Head Coach Michael Maguire said: “It’s a great thing for the Club and the team that Sam has agreed to sign long term with us.
“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.”
Burgess played 79 games for Bradford before moving Down Under in 2010, and is widely regarded as one of the best English imports in the NRL for the past 20 years.