From 1969 to 1990 and from 1993 to 2001, Baan held various positions with the electronics firm Philips, the last few years as a member of the Board of Directors. He held a number of executive positions and sat on a number of supervisory boards. Baan was, for example, a member of the Supervisory Board of the AMC-UvA and chairman of the Supervisory Board for the Netherlands Authority for the Financial Markets. In addition, he was also chairman of the Supervisory Board of Wolters Kluwer and Van Gansewinkel Group, non-executive chairman of Dockwise, vice-chairman of the Supervisory Board of Imtech and supervisory director at Océ.
Adri Baan had been a member of the Supervisory Board of the University of Amsterdam (UvA) since 2005. He was also an advisor to the Supervisory Board of the Amsterdam University of Applied Sciences (AUAS/HvA). From 2001 to 2005, he had been a member of the AUAS/HvA Suprervisory Board.