Notenboom was a member of the Catholic People's Party and later the Christian Democratic Appeal when the former had merged into it in 1980.

[1] As financial specialist of the Catholic People's Party he was influential in the Night of Schmelzer, which led to the fall of the Cals cabinet.

[1] He was adjunct secretary of the Nederlandse Rooms-Katholieke Middenstandsbond from September 1952 to January 1956.

[1] In 1988 he obtained his title of doctor in economic sciences with a thesis on budget law of the European Parliament.

[4] Notenboom was bijzonder hoogleraar [nl] (professor not paid by University funds) of problematics of small and medium-sized enterprises between 1991 and 1994 at Eindhoven University of Technology.