Jones joined the region on loan from Welsh rivals Cardiff Rugby earlier this season and has committed his future to the Men of Gwent.
The former Welsh Under-20 international adds a wealth of experience to the squad, having made 120 appearances for Cardiff during ten years in the capital.
The 29-year-old joins fellow new recruits JJ Hanrahan, Sio Tomkinson, Max Clark, Angus O’Brien, Bradley Roberts, Rhodri Jones, Sean Lonsdale and George Nott in agreeing terms with Dragons.
Director of Dragons Rugby Dean Ryan said: “We’re really pleased that Lewis has signed for us after impressing throughout this season.
“Lewis brings energy to the squad, has shown his quality again since returning from injury and his experience will be vital for helping develop the young players coming through our system.”
Lewis has made six appearances for Dragons, having returned to full fitness in March following a bicep injury.
Jones said: “I’m delighted to sign with the Dragons and excited about the future here.
“It’s a fantastic group of boys here who have really welcomed me into the set-up and who are all determined to bring success to the region.”