Ady Pennock has secured his third signing of the summer with the capture of Gabriel Zakuani on a one-year deal.
The 31-year-old joins the Gills having failed to agree a new contract at Northampton Town, and boosts the club's defensive options with Alex Lacey and Luke O'Neill having already agreed terms at Priestfield.
Zakuani, a Congolese International, played under former Gills boss Justin Edinburgh last season at Sixfields, racking up 26 appearances in total and scoring two goals.
On capturing his signature Pennock said: "I'm really pleased to get Gabriel on board. Naturally he was attracting interest from other clubs but I'm delighted he has committed his future to us for the forthcoming season.
"Along with Alex and Luke he will provide stern competition for places in defence, and we very much look forward to working with him."
The defender began his career at Leyton Orient before joining Fulham for a million pounds in the summer of 2006.
Spells at Stoke, Peterborough and Kalloni in Greece followed prior to signing for the Cobblers last summer.
On securing his future Zakuani told the club: "I'm delighted to have joined Gillingham; as soon as I met the Manager and Peter Taylor I felt it was the right place to continue my career and I can't wait to get going.
"The management have made some great signings already and I'll do my best to help push the club up the League One table."
Zakuani featured in the African Cup of Nations earlier this year for Congo, starting in the 1-0 win over Morocco.