The 20-year-old Northern Ireland U17 international makes the switch to Solitude following a year at the Brandywell.
Storey kicked off his career as a youth at Portadown before breaking into the first team squad which earned him a move to Portsmouth.
He was loaned out to Southern League side Gosport Borough and then to Carrick Rangers before leaving Fratton Park permanently and linking up with the Candystripes.
City manager Ruaidhrí Higgins said: “Gerard is a fantastic lad to work with and I want to wish him every success going forward.”
Best of luck Gerard.
Tags: