Gills complete Wallace signing
The experienced striker, formerly of Glasgow Rangers and Leeds United, was out of contract at the Reebok and has signed a two-year deal.
Gillingham chairman Paul Scally, who flew to Spain where the 32-year-old was on holiday, was delighted to capture Wallace, who will now join the club on July 2.
"Although there is no fee involved, this is still the biggest acquisition the club has ever made," said Scally to the club's official website.
"Rod (Wallace) was top of the manager's list of players we ought to be chasing during the close season, and I know Andy (Hessenthaler) is cock-a-hoop that we have pulled off this deal.
"A lot of other clubs were also interested, so I am particularly pleased we have been successful.
"This is a momentous day for our football club and shows the doubters and those who suggested we might be dithering, that we mean business.
"Despite two successful seasons in Division One, we do not intend to rest on our laurels. Our record of finishing higher each year is one we fully intend to keep up."
The Lewisham-born star scored three goals in 19 appearances for The Trotters last season, having bagged 43 goals in 76 appearances for Glasgow Rangers in three years at Ibrox.