Wenaweser was educated at the University of Zurich, the Graduate Institute of International Studies in Geneva, and the Bavarian Academy of Sciences and Humanities in Munich, Germany.

In this capacity, he has been particularly active in developing the International Criminal Court (ICC) further.

Within the Assembly of States Parties of the ICC, Wenaweser chaired the Special Working Group on the Crime of Aggression from 2003 and 2009.

[1] In 2007, he was elected to a three-year term as the president of the Assembly of States Parties.

Between 2003 and 2005 Wenaweser also served as chairman of the ad hoc Committee on the Scope of Legal Protection under the Convention on the Safety of United Nations and Associated Personnel[2] From 2004 until 2005, he was vice-chair of the Open-Ended Working Group on Security Council Reform.