"He's proven that he can score runs and take wickets. We could never have turned down an ex-England player. Chris's arrival is a big boost for the team."
Cheshire have lost former Nottinghamshire and Staffordshire batsman Graeme Archer this season due to work commitments and also former Hampshire allrounder Simon Renshaw.
But Schofield's signature and the new signing of ex-Lancashire batsman Mark Currie and former Derbyshire duo Nathan Dumelow and Steve Selwood give the county a solid base on which to build success this season.
Former Cheshire all-rounder Simon Marshall has joined Lancashire this season, having figured for Hardstaff's team briefly last term.
"We've lost Graeme and Simon, so to sign Chris and Mark, who are good friends, is great news for the county," said Hardstaff.
"We're looking forward to both players doing well for us. It's a new start for both of them."
Schofield made his England Test debut at Lords in 2000 and scored a half-century in his second Test at Trent Bridge.
But over the last few years Schofield had limited opportunities with Lancashire first team, although he has scored over 2,000 first class runs with a top score of 99.
Lancashire manager Mike Watkinson said: "Chris is an extremely talented cricketer who has perhaps not reached his full potential at the club.
"We feel it is an appropriate stage of his career for him to seek more regular first-team cricket."