Before his appointment to Director-General of Internal Market and Services at the European Commission in 2007, Holmquist served as the director-general of Fisheries and Maritime Affairs, deputy director general of the DG Budget and director of the DG Agriculture at the European Commission.
Before working at the European Commission, he worked for the Swedish Ministry of Finance and, from 1987 to 1993 he was Counsellor for Financial Affairs at the Swedish Embassy in Washington D.C., USA.