A number of clubs including Wests Tigers, Parramatta and Canberra were reported to be scrambling to sign the versatile 29-year-old.
But the prospect of challenging for a premiership with the Sharks was the biggest pull for Lewis, who signed a four-year deal.
“I have a genuine belief the Sharks are moving in the right direction,” Lewis said.
“I sat down and dwelled on the decision… it was a tough one to make.
“But the players at Cronulla including Paul, Wade and Todd, plus the outstanding facilities and good lifestyle, I’m stoked to be coming here next year.
“I definitely believe the Sharks can do it [win the premiership].”
Sharks skipper Paul Gallen said Lewis’ pedigree would be a welcome boost to the squad.
“No matter who your coach is, a good playing roster is needed to play well,” Gallen said.
“Signing Lewis does a lot for this club… It goes to show the steps forward the club has been taking and says a lot as to where the club is going.”