The pacey hitman will aim to replicate his sensational strike rate for Rushden & Diamonds at the Priestfield Stadium
Jamaican-born Jackson joined the Gills in January 2008 for £150,000 after establishing himself as one of the most lethal marksmen in non-league for Rushden & Diamonds.
A diminutive yet lightning-quick striker with a powerful right foot, Jackson started out at Dulwich Hamlet before moving to Nene Park in August 2004, where he smashed 42 goals in almost 100 appearances.
He scored 19 times in 2006/07 and already had another 18 by the time manager Mark Stimson snapped him up midway through the following season.
Despite being born in Jamaica, Jackson holds a Canadian passport and featured in all three of the Maple Leafs’ games at the 2007 FIFA U20 World Cup.