Sammut, who helped London Broncos win promotion to the top division this year, has signed a two-year contract.
The 31-year-old utility-back made 38 top-flight appearances for Bradford Bulls in 2012-13 and 20 with Wakefield Trinity Wildcats from 2014-15.
He lweft London for “personal reasons” last month after two seasons with the club.
“It’s a massive opportunity for myself to play for one of the biggest clubs in Super League,” he said.
“I’m really excited to get stuck in and play my part. The whole environment at the club is something that will help me progress my game even further and I hope I can bring a different style of rugby and attacking flair to the team, as I’ve been around the game for quite some time.”
Wigan coach, Adrian Lam described Sammut as “a player who has can produce a little bit of magic and keep defences guessing”.
He said: “He’s a livewire type of half-back, and he’ll add to our options in the halves.
“Having spoken to him, Jarrod is hungry to show he has what it takes to produce the type of footy he is capable of on a consistent basis for a club the size of Wigan.”
Warriors’ executive director Kris Radlinski added: “When we heard the news about Jarrod’s release from London we acted quickly to meet him. It was clear that he was a very motivated guy who still had a burning ambition to play at the top level.
“We believe will strengthen our group.”