Following 10 years at the High Assembly, Noelle Lenoir joined the regulation management of the newly formed national data protection authority Commission for Information Technology and Civil Liberties (Commission Nationale de l'Informatique et des Libertés (CNIL) as Chief Legal Officer, from 1982 until 1984.

In 1984, she joined the Council of State (the Conseil d'État is the French administrative Supreme Court) where she was appointed 'Rapporteur Public" (Advocate general).

She left her position at the GEE in 2000 to travel to the United States where she was, an adjunct law professor at the Law university of Columbia, New York City before joining the Paris Bar in 2001, Noëlle Lenoir was appointed in 2002 Junior Minister for European Affairs by Prime Minister Jean-Pierre Raffarin.

Finally, she is the first woman appointed, with her counterpart the German minister of European affairs, to the position of General Secretary for France-German Cooperation (SGFA).

In 2006–2007 she was appointed by the French Minister of Justice to conduct an evaluation of the status of the European Company (SE) (report delivered on 19 March 2007).

Noëlle Lenoir joined JeantetAssociés in 2009 as a partner where she headed the European department (competition law, litigation and regulatory).

[4] Between 22 May 2017 and 30 April 2020, she was a member of the panel of independent experts or ICRP (along with Theo Waigel, former Finance Minister of Germany, and Lord Gold) designated by Airbus to examine the compliance within the company and monitor the improvements needed.

After having been appointed by the French Minister of Justice, she acted as Commissioner under the 1970 Hague Convention on the taking of evidence abroad in civil and commercial matters in charge of ensuring compliance of the discovery process set up in relation with the tragic fire at the Grenfell Apartment complex in London with the French Blocking Statute and GDPR.

[2] Furthermore, she is the Founder and President of Cercle des Européens,[2] a think-tank which operates as an ideas exchange group on socioeconomic and political stakes of the 21st century Europe.

Noelle Lenoir is also President of the Comité Droit et Débat Public, which gathers lawyers interested in popularization of legal issues.

She was appointed as Chairman of the Scientific and Ethics Committee of the Parcoursup platform by an order issued by the French Minister of Higher Education and Research.