Andresen replaces former Vestas CFO Henrik Norremark, who was also deputy chief executive. Norremark left the company in February as part of a major boardroom reshuffle at Vestas (see 'Vestas in turmoil').
Prior to leaving Vattenfall in 2011, Andresen held roles at financial group Nordea, Den Norske Bank, the Nordic Investment Bank and industrial group Kvaerner.
Speaking about the appointment, Vestas chairman Bert Nordberg said: ""With Dag Andresen at the table Vestas will be provided with one of the absolutely best forces within this area.
"His professional background, the significant results he has achieved and not least the testimonials he gets, are all very convincing. As he moreover has a thorough knowledge of the energy sector from within, we have fulfilled all our wishes for the new CFO profile."
Andresen arrives shortly after former Sony Ericsson CEO Nordberg, who was voted into the role of chairman last month after a period of intense upheaval at Vestas.
2012 has seen the departure of senior executives including CTO Finn Madsen and offshore chief Anders Soe-Jensen, whose replacement Hans Jorn Rieks was sacked after only three months in the role.