[4] Leu was born in 1961 in Zürich, Switzerland however her parents hailed from Grisons.

In 1989, after graduating, Leu entered the Federal Department of Foreign Affairs and initially was employed as a trainee in Bern, Paris and Geneva.

[7] Later she became vice chairman of the Swiss delegation in Cairo, and a member of the group responsible for dealing with the nuclear program of Iran.

Before serving as the Ambassador to Iran, Agosti was the head of the African and European Department of the Ministry of Foreign Affairs of Switzerland.

Her husband, who is a biologist, an expert, and a researcher in the field of ants, is busy working in Iran.