Brown, 28, will join the Club with immediate effect and has agreed an extended contract until the end of November 2018.
He played for Cronulla until the end of the 2009 season before joining Wests Tigers and moved onto play for Canterbury Bulldogs early in the 2012 campaign. He was a member of the Canterbury side that lost to South Sydney in the 2014 NRL grand final.
In the last two seasons he has been back at Cronulla. Brown is credited with 39 tries in 132 NRL games.
Leigh Centurions head Ccach Neil Jukes said: “I am really excited to bring in a guy of Mitch’s experience and what he can offer to our team and culture.
“He is an experienced back-line player who can play wing, centre or fullback and he’s not here for the short term.
“I have spoken to Mitch personally and he is excited by the challenge to enhance what we are doing at Leigh Centurions.
“He has a lot to offer to the game and we have done a lot of research on him as a player and as a person and every feedback has been positive.
“As Peter Sterling said recently, Mitch is a great, solid, quality player who has done a great job at every club he has been at.
“When someone of Peter Sterling’s stature says that, it is a big recommendation. We want that sort of player and person in our group.
“I look forward to welcoming Mitch to continue this year’s journey and beyond.”
Leigh Centurions Owner Derek Beaumont said: “This is yet another statement of our intent as a club to build a Super League side and our ability to convince proven top quality players that we are a club going places.
“Mitch will add strike to our side going into the Middle 8s and is a proven player that we can move forward with over the next couple of years.
“I have always said I will invest what is necessary to achieve our goals and keep improving our squad and it doesn’t stop here.
“It is my job to give the coaches the best possible tools to do the job in hand. They have worked hard to identify the target and I am very excited by this addition and I am looking forward to seeing Mitch pull on a Leigh Centurions shirt.”