 Dempster accepted the position of academy manager at Mansfield at the end of the 2014–15 season.On the resignation of club manager Steve Evans in February 2018, Dempster assumed the role of caretaker manager, until new manager David Flitcroft was confirmed 1 March 2018.Dempster was promoted to the position of Mansfield Town manager when Flitcroft's contract was terminated 14 May 2019.