The defender was released by Leeds United earlier this month.
The 21-year-old central defender was told he could leave Leeds this summer after failing to make an impact on the first-team at the club.
But it was announced by Chester FC today that Killock would be joining the club permanently, after spending time on loan with the club throughout the 2013-14 season.
The young defender, who turns 22 next month, took to Twitter to show his happiness at joining the National League outfit.
Killock, who has also spent time on loan at Alfreton Town, Halifax Town and Stockport County during his stint at Thorp Arch, never made an appearance for the Yorkshire club.
He came close on four occasions, making the bench for games against Accrington Stanley and Sunderland in the domestic cup competitions and Millwall and Watford in the league.
However, Killock never looked likely to make the grade at Leeds United and hopefully he can find a decent career off the back of his move to the Deva Stadium.