“I’m really looking forward to this new challenge,” he said.
“The club has a great profile and stature in the game and I hope to be able to contribute to developing that wonderful culture
“I am told Saints have the best fans in the game and I can’t wait to engage with them.
“I’m really looking forward to this next chapter in my life.”
After playing his junior football for Yamba Eagles and Lower Clarence Magpies, Luke made his first grade debut for Cronulla in 2006.
He went to make close to 150 appearances for the Sharks, scoring 10 tries, before moving to the Titans in 2012.
In-between, from 2006 to 2014, he never missed a first grade match though injury or suspension and his run of 215 games is the record for most consecutive appearances in the NRL.
Douglas has also played Country Origin and been 18th man for the New South Wales State of Origin team.
“His leadership will be important to our younger players too and we are delighted to secure his signature for the next three years.”