The 29-year-old has penned a three-year deal at Villa Park, having spent three years at Saints, the first of them on loan from Liverpool.
In that time he netted 41 Premier League goals for the south coast club, playing a pivotal role under Ralph Hasenhuttl – but with just one season left on his deal he opted to move on rather than renew and becomes Villa’s fourth senior signing of the summer.
That follows deals for Ashley Young and Emiliano Buendia, with Leon Bailey becoming the third after joining from Bayer Leverkusen earlier on Wednesday.
“Danny is an outstanding Premier League footballer who has scored goals wherever he has played,” manager Dean Smith said.
“He is also a top professional with a great character who will be a leader in our squad and a role model for our rapidly developing young academy players who are now in and around the first team. I am delighted to welcome Danny to our great club.”
Ings, who has three caps and one goal for England at senior level, joins as Villa restructure their front line ahead of the likely departure of star and captain Jack Grealish.
The playmaker is the subject of a £100m bid from Manchester City and his move is likely to go through in the coming days.
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