The Panthers on Tuesday confirmed they had released the controversial Jennings from the remainder of his contract.
Jennings, 24, says he is excited to change clubs and work with Sydney Roosters halfback and Blues teammate Mitchell Pearce.
“The Roosters have a talented roster and I’m excited to have joined the team," Jennings said in a statement from the Roosters.
"I have met with Trent Robinson and am looking forward to getting to know my new teammates, getting stuck into training, working hard and playing alongside guys like Mitchell Pearce who I have already played with at Origin level.”
Roosters chief Brian Canavan said the signing of Jennings adds further depth and experience to the Roosters backline.
“A player of immense talent, Michael is a great addition to our squad," Canavan said.
"With the release of BJ Leilua and the lengthy loss of Tautau Moga to injury, Michael will add potency to our backline.
“Having already played in excess of 100 matches in the NRL and numerous representative games, Michael brings considerable experience to the club.
"I’m sure he will both add to and compliment what we are working towards building here at the Roosters.
“We welcome Michael to the Roosters family and are pleased to have him as part of our club for the next four seasons.”