In September 2010 HRVP Catherine Ashton announced the first class of European Union ambassadors to be posted abroad following the entry into force of the Treaty of Lisbon.

[11][12] She served for four Secretaries General at the European External Action Service: Pierre Vimont, Alain Le Roy, Helga Schmid and Stefano Sannino.

In April 2024 EU HRVP Josep Borrell nominated Eichhorst as the next EU Ambassador in Cairo https://www.eeas.europa.eu/eeas/eeas-high-representative-josep-borrell-nominated-new-heads-eu-delegations-upcoming-diplomatic_en Eichhorst joined the European Commission in Brussels in 1996, where at the then DG IB External relations,[13][circular reference] led by Ambassador DG Juan Prat,[14] she held various positions in charge of the Euro-Mediterranean Barcelona Process — now Union for the Mediterranean.

In 2008 she was promoted to head the Political and Economic Affairs, Press, Information and Culture department[27] at the EU Delegation in Damascus, Syria where she worked and lived until she took up her position as European Union ambassador in Beirut, Lebanon.

Ambassador Eichhorst holds two MA degrees: languages and cultures of the Middle East, Catholic University in Nijmegen, with her thesis on Egyptian women writers;[33] and international relations, Université libre de Bruxelles, describing the challenges of NATO's Mediterranean Dialogue.