"There's no better place for me to sign a long-term deal than Gillingham," Spiller told BBC Radio Kent.
"I've been a bit here, there and everywhere with short-term contracts over the last couple of seasons."
Spiller made 138 first-team appearances during his first spell with Gillingham before joining Millwall in the summer of 2007.
He left the New Den two years later after struggling to make an impact and has since spent time at Wycombe, Welling and Dagenham & Redbridge
"Gillingham are my local club, and even when I wasn't with them I was listening out for their results, checking the paper and keeping in touch with the boys," Spiller added. "The club's a part of me."
The midfielder has made 20 appearances for the Gills this season, scoring twice, after winning a contract with the Kent club following a successful trial in the summer.
His previous deal was due to expire before Saturday's game with Stevenage.
Source: BBC Sport
Source: BBC Sport