Knox's first managerial role came in a player-manager capacity when he returned to first club Forfar in 1976, spending four years in the dual role. In 1980, Knox became assistant to Alex Ferguson at Aberdeen, helping the team to two Scottish Cups, the European Cup Winners' Cup and subsequent European Super Cup in his three years with the Dons. In 1983, Knox returned to management with Dundee, where he would spend two-and-a-half years, with a best finish of sixth place in 1984–85 and 1985–86, narrowly missing out on UEFA Cup qualification.
Knox's first managerial experience was as a player-manager at Forfar from 1976 to 1980. In 1980, he became an assistant coach under Alex Ferguson at Aberdeen, helping the team win two Scottish Cups and the European Cup Winners' Cup over three years. In 1983, Knox returned to management with Dundee, where he managed for two-and-a-half years, reaching a best finish of sixth place in both 1984–85 and 1985–86.