Walker has put pen to paper over a two-year deal at Turf Moor to play under Scott Parker, who he played alongside at Tottenham Hotspur earlier in his career.
The 35-year-old has had a remarkable career for club and country, winning six Premier League titles, two FA Cups and one Champions League. He has been named in the Premier League Team of the Tear on four occasions.
Walker has won 96 England caps to date and is still hungry for more with a World Cup on the horizon next summer.
"I'm delighted to be here," he said. "When I spoke to Scott and heard about his plans for next season, it was an opportunity I jumped at.
"He's done an amazing job here, guiding the club back to the Premier League with a 100-point haul, and now we're looking forward, together, at being back in the greatest league in the world.
"Burnley had a tremendous campaign last season, built on an incredible defensive record, and I can't wait to come in and add my experience and quality to what looks an exciting squad."
The defender began his career at Sheffield United, playing against the Clarets in the 2009 play-off final at Wembley.
Walker's impressive performances saw him snapped up by Tottenham Hotspur, where he established himself as one of the best defenders in the country.
He then made the move to Manchester City, where he took his game to new heights including the Premier League, Champions League and Super Cup treble in 2023/24.
Walker spent the second half of last season on loan at Italian giants AC Milan and now arrives at Turf Moor as the Clarets prepare for life back in the top flight.