Herring initially became joint-manager of the Berkshire outfit in 2017 with Jon Boardman, before taking sole charge in February 2018.
Under Herring, the Crusaders avoided relegation in both the 2017/18 and 2018/19 seasons.
Despite being bottom of Vanarama National League South, Hungerford achieved seven points from four games before the remaining regular season matches were cancelled.
Chairman Patrick Chambers paid tribute to the departing boss: “I want to personally thank Ian for his dedication to the role and it was he that persuaded me to get involved at the back end of last season.
“Ian took over in difficult circumstances after Bobby Wilkinson left the club and our fans loved his determination and spirit. He was adamant he would again escape relegation this season.
“I sincerely hope he gets the opportunity to move on with his progressive management style in the very near future”.