The 23-year-old attacker attracted interest from several clubs, but the Owls have won the race for his signature as they prepare for life in League One.
Barry signed for Villa from Barcelona in 2020, but had nine loan spells away from Villa Park, including a brief stint at Portman Road in the first half of the 2021/22 season.
He was set to join Hull City last summer in a deal worth £3.5 million, but the transfer fell through after the Tigers were hit with a transfer embargo.
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Louie Barry, pictured during his brief loan spell at Sheffield United. (Image: PA)
The forward instead moved to rivals Sheffield United on loan, but Villa recalled him following an injury. Barry then returned to Stockport County for a third spell at Edgeley Park in the second half of the 2025/26 campaign.
He has now put pen to paper on a four-year contract at Hillsborough.
On signing for Wednesday, he said: “I’m buzzing and I can't wait to get started – it’s just about finding a home and this is the place I want to be for the next part of my career.
“It's now time to settle down and find a home and I think that will come out in my performances as well.
"I've walked into a really warm atmosphere. Getting a good pre-season under my belt is a massive thing to build connections and to get used to the style of play straight away.
“I feel like I can progress at the same speed as the club wants to, which is fantastic. To call a club your own is just a great feeling.”
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