The 23-year-old made his Super League debut for Wigan in 2016, making 18 first team appearances for the Warriors as well as spending time on loan at Swinton and Toronto.
Back-rower Wells is now following Joe Burgess in swapping the Warriors for the Red Devils ahead of the 2021 campaign.
“When I watched Salford players walk out before a match as a young fan, I’d look at them and was in awe,” Wells said.
“The thought of doing that myself is surreal. I’m looking forward to starting a new chapter in my career and to do that at my hometown club really means a lot.
“I was one of those kids, looking up to the players when I went to watch Salford with my brother and my dad.
“I was a season ticket holder for 10 years and it was players like Andy Coley and Stuart Littler who inspired me to start my career, so hopefully I can be in the position that they were.”
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