Trained as a civil engineer, Nelly Wenger began her career at the Ecole Polytechnique Fédérale de Lausanne then in 1982 joined Urbaplan, a Lausanne-based bureau active in the fields of project management, economic development, transport, the environment and urban planning. There she managed major transport infrastructure projects (road and rail) and was placed in charge of economic and urban development strategies in Switzerland and Africa.

In parallel to her work for Urbaplan, she also held teaching posts at the Ecole Polytechnique Fédérale de Lausanne and the University of Geneva, where she set up and ran a postgraduate programme in urban management and construction.

She was subsequently appointed head of the regional planning department of the canton of Vaud, and carried out far-reaching reforms of the department. She initiated and developed a policy aimed at creating economic development centres (365 hectares), introducing financial and tax incentive measures and guaranteeing efficient economic development. She was then tasked by the government to chair the committee in charge of implementing this policy.

In 1999, Nelly Wenger joined the board of management of Switzerland's national exhibition Expo.02, a project comprising four sites of 40 hectares each, more than 40 themed exhibitions, 1,300 cultural events and a budget of 1.6 billion Swiss francs. She was responsible for making the event an unqualified success, with more than 10 million admissions during the six months that the exhibition was open in 2002.

In 2003, she was appointed CEO of Nestlé Switzerland (with a turnover of CHF 1.4 billion, 2,500 employees and eight production sites).

On 1 October 2007, she founded her own company, Nelly Wenger Associates, an independent strategic management bureau that operates internationally, within which she has successfully realised a number of major projects.

Nelly Wenger is currently director of the R4 project and is responsible for concept development and realisation. This "Sculpture and Visual Arts Portal" occupies a site of more than 25,000 m2 on Ile Seguin, an island in the Seine (Greater Paris).

She is also a member of the Strategy Advisory Board of the Ecole Polytechnique Fédérale de Lausanne and of the Académie Suisse des Sciences Techniques.