Mr McCormick has been associated with the Candy Stripes for over 50 years and has worked tirelessly for the club during those years, being a Development Committee member, a Director, a Friends of Derry City member, and on the club's lottery, monthly draw and also many fundraising committees.
In the 1980's Edgar was a former member of the club's Du Pont Supporters’ Club, he also served on the Board of Directors at the club in the 1990s and followed the Brandywell men home and away.
The club issued a statement saying: "Derry City FC is deeply saddened by the death overnight of our dear friend, Edgar McCormick.
"Edgar has been a dedicated lifelong supporter, and his passing will be sorely felt throughout the club.
"Edgar served in a wide variety of roles at the club, giving long standing service to many of the voluntary committees around the club. He also served as a Director of the club on a number of occasions since our entry into the League of Ireland.
"On behalf of the Board, management, players, staff and supporters of Derry City we wish to extend sincerest condolences to Bridie and the entire family circle.
"May his gentle soul Rest In Peace."
Former captain Barry Molloy also took to social media to pay his respects stating on Twitter: "Very sad to hear the passing of Edgar. A gentleman who will be missed by so many. Brilliant servant to Derry City over the years. RIP."