Stewart, 30, has played 184 NRL matches since making his debut for the Manly-Warringah Sea Eagles in 2003. Stewart has played in four NRL Grand Finals with the Sea Eagles in 2007, 2008, 2011 and 2013, claiming premierships in the 2008 and 2011 seasons as well as the Clive Churchill Medal for man-of-the-match in the Grand Final in 2011.
Stewart has also represented Australia in five Tests in 2008 and 2009; NSW in five State of Origin clashes in 2009 and 2012; played three games for Country Origin in 2008, 2010 and 2011; and played for the Prime Minister's XIII against Papua New Guinea in 2009.
Rabbitohs Head Coach Michael Maguire is delighted that the Rabbitohs have secured the services of Stewart for the next two seasons.
"Glenn is one of the lynch-pins to the extended success the Sea Eagles have had over the past decade and he will bring a lot to our Club," Coach Maguire said.
"Glenn has achieved a lot throughout his time in the game and the experience that he has at the highest levels on the biggest stage, as well as his leadership qualities, will be invaluable to the young players we have coming through in our squad.
"He's a tough player in attack and defense that can ball-play as well, and we're looking forward to adding him to our squad during the next pre-season."
Stewart says he is excited about the new beginning that lies ahead when he joins the Rabbitohs.
"I've really enjoyed the times I've had at Manly over the past 12 seasons but circumstances at the Club have led to me moving on at the end of this year," Stewart said.
"I'm really excited about moving onto that next chapter of my career next year and I'm looking forward to the change, and the challenges, that will come with joining the Rabbitohs," Stewart said.
"I'm glad to have this sorted out early in the season so that I can now concentrate on finishing off the job I need to do for Manly this year."
Name: Glenn Stewart
Date of Birth: 11 January 1984
Place of Birth: Wollongong, NSW
Position: Second row/lock
Junior Club: Wests Wollongong
Rep Honours: Five Tests for Australia (2008-09); five games for NSW (2009, 2012); three games for Country Origin (2008, 2010-11); one game for Prime Minister's XIII (2009)
Awards: Clive Churchill Medal (2011); Dally M Second Rower of the Year (2008)
NRL Games: 184 for Sea Eagles (2003-current)
NRL Points: 108 from 27 tries
NRL Debut: Sea Eagles vs Broncos, Suncorp Stadium, 26 July 2003 (Rd 20)