The 24-year-old France back joined on the same day that scrum-half Matty Smith moved to rivals St Helens on a three-year deal.
Escare, who can also play on the wing, has a one-year option with the Warriors after the 2017 season.
"After four years in Super League with Catalans, I feel the time is right for a change for me," he said.
"I grew up in France watching and admiring Wigan and it will be an honour and a privilege to represent the Cherry and Whites."
Wigan have also re-signed 20-year-old winger Liam Forsyth after a one-year spell at rugby union side Bath, but half-back Matty Smith has re-signed for St Helens.
Super League champions Wigan Warriors have signed Catalans Dragons full-back Morgan Escare on a one-year deal.