The 32-year-old left Wigan Athletic by mutual consent last week in order to be closer to his family, and he has now rejoined Burton, where he made 44 appearances during the 2008-09 campaign.
Buxton has put pen to paper on a one-year deal at the Pirelli Stadium, where he will join up with manager Nigel Clough for a third time following previous spells at Burton and Derby County.
"It's nice to get it done and dusted and to be back, and especially where the club has come from since I was last here and now to be part of the future," Buxton told the club's official website.
"After winning the league with Burton Albion, the opportunity came to join the Rams and a new chapter in my playing career. I went in as sixth choice and worked my way up there.
"I had a good relationship with Nigel Clough there and giving me the opportunity to sign for Derby County is a big reason why I have come back to Burton Albion. This is a Championship club now as well and it's a good fit for me at this time of my career."
Clough added: "He has come on as player since (his first Burton Albion spell) and very nearly made the Premier League with Derby. He's a very good, experienced defender.
"He knows the challenges we face at the club the size of Burton. He'll be under no illusions and he will fit straight in. As he is a player we know well, there is less settling in time. He knows what's expected and that certainly helps. His experience will be vital in the dressing room next season for another tough year."
Buxton made 42 appearances for Wigan last season but was unable to prevent the Latics from suffering relegation into League One.