Known as Nana, the versatile former Chelsea trainee impressed in a loan spell at Sixfields last season and has been snapped up on a two-year deal after parent club Peterborough's promotion to the Championship
Northampton boss Gary Johnson told the club's official website: "As our supporters would have seen from his loan spell, Nana can play as a right-back or cover in midfield.
"He has got power and pace and we have agreed to bring him in on a permanent deal having seen him improve each game when he was with us on loan."