[2] From 1983 to 1993 Walch represented the Progressive Citizens' Party as member of the Steering committee of the European Democrat Union.

[1] He served as the Liechtenstein minister of foreign affairs from 2001 to 2005 in the first Otmar Hasler cabinet.

[3] Walch belongs to various professional organizations, including the New York State Bar Association, the Liechtenstein Law Society and the German-Austrian-Swiss Registered Association of Lawyers (DACH).

[1] From 2006 Walch was a member of the board of directors of the Liechtensteiner Volksblatt until it ceased operations in March 2023 due to declining subscriptions and rising costs.

[5] Walch married Margrit Keller (10 December 1955 – 2024) on 22 November 1980 and they had six children together.