Marlies Amann-Marxer went to St. Elizabeth Business School in Schaan, where, in 1969, she earned a trade-diploma. After that she travelled to Neuchâtel, Geneva and Torquay to learn the languages and for business trips. Additionally she worked from 1970 on in various commercial jobs at the National bank of Liechtenstein, the international steeltrading institute and the Pattchom Int. Eng. AG in Vaduz. From 1989 to 1995 she was employed in her husband's company, the Amann Architektur AG where she was working on human resources, accounting and finances. From 1993 to 2001, Amann-Marxer was a lay judge of the Liechtenstein Criminal Court, and from 1997 to 2003, a spare lay judge of the Administrative Court.
Amann-Marxer's first political office was the membership in various community-commissions as well as the election as a member of the local council of Eschen in 2000, where she was holding the portfolio for schools. In 2005, Amann-Marxer was elected to serve as a Member of Parliament in the Landtag, the parliament of Liechtenstein. After the 2013 parliamentary election, Amann-Marxer was appointed to serve under the new government Prime MinisterAdrian Hasler as Minister of Infrastructure, Environment and Sport.