The deal will keep Bird at the joint venture club until at least the end of the 2024 season, although the club's official media release on Monday evening made no mention of whether he has a third year in the way of an option available.
It had previously been reported during a long-winded contract circus for Bird that the star utility - who can play at fullback, centre, five-eighth, second row or lock - was holding out for a third year on the deal.
All of the Dolphins, Parramatta Eels and Wests Tigers were believed to have shown interest in Bird at one point or another, with the Tigers maintaining they were in the running for the star as recently as the weekend.
Reports that Bird was yet to sign a contract with the club were put at ease by club authorities over the weekend, stating that while the contract hadn't been signed, his manager had agreed to terms.
Dragons general manager of football Ben Haran said it was a pleasing development.
"Jack is an out-an-out footballer, a proven winner and a fantastic competitor who has, and will continue to add, great value to the team over the coming seasons," Haran said.
"Jack's is a great character around the club and his retention is a win for everyone involved at the Dragons, including our passionate Red V members and partners."
He said in the statement that he was enjoying being back at the Dragons.
"St George Illawarra is where I first started my career and I'm proud to remain a Dragon," Bird said.
"The club gave me the chance to come back and play first grade after all the injuries I faced earlier in my career.
"It has been an opportunity I'm grateful for and one that I have enjoyed over the past 18 months particularly with the support of my family and friends close by."
Bird has played 115 NRL games and scored 27 tries. His career looked all but over after a stint in Brisbane which saw injury hold him to just 17 games over two seasons, but he has played 32 games since his return to the Dragons at the start of 2021, and become one of the club's most consistent performers in multiple positions.