Date of birth
The Midfielder arrived at the Spireites as one of three signed on January 4 and joins the club on a permanent basis.
Kay joined Sky Bet Championship club Barnsley in 2016 from AFC Flyde and made his debut for the club against Bristol City in October of that year.
He then went on-loan to Tranmere Rovers in November and made two substitute appearances during his time at Prenton Park.
Kay made his Spireites debut in the Sky Bet League Two clash with Accrington Stanley on January 6.