Molloy, who joined the Wildcats in 2013, was out of contract at the end of the 2015 season and is delighted to stay at Belle Vue under new coach Brian Smith.
“I have really enjoyed playing under Brian Smith,” he said. “I am looking forward to getting back to work in pre-season and stamping down a starting position.”
Smith said: “Jonny Molloy’s re-signing for the Wildcats was based on his series of outstanding Super League matches soon after my time began as a coach.
“Free of injuries in 2016 after a big off-season of work, we expect Jonny to become an important contributor to our success.”
Meanwhile, former Castleford Tigers half-back Rangi Chase’s four-year contract at Salford has been officially terminated after two seasons.
The 29-year-old former England international missed the Red Devils’ last four matches of the 2015 season after being suspended for apparently failing to report for training on time and going on sick leave.
Six weeks ago Salford owner Marwan Koukash announced he had granted Chase a free transfer. But the club opted for the disciplinary hearing route at which the New Zealand-born stand-off was represented by the GMB union.
A propsed move to Leigh Centurions appears to be stalling over salary-cap issues.