He played professionally for a number of European clubs, and helped Gent win the Belgian Cup.
MVV finished 16th in the 1981–82 Eredivisie season and were relegated to the secondary Eerste Divisie league, and Busk left the club in the summer 1982.
[6][7] He operated as a right-back in Denmark's first three games against France, Yugoslavia, and Belgium, but switched to the other flank for the Danes' dramatic semi-final against Spain in Lyon, with John Sivebæk coming in on the other side of the defence.
[6] Busk played well in the first round as Denmark topped the group, but endured a torrid time during their second-round 5–1 defeat to Spain, and conceded one of the two penalties given away by the Danes in the second half.
After the World Cup, Busk moved to play for French club AS Monaco in the Ligue 1 championship in the summer 1986.
[2] After the European Championship, Busk ended his international career, and moved back to Denmark in the summer 1988.