Mie graduated as an engineer at Østfold University College and has subsequently taken various courses in environmental and resource efficiency. Before she started in Østfold Research, she worked for a period as a teacher, a period in the process industry and also in finance.
Mie was employed in Østfoldforskning from 1990 until she joined as a partner to LCA.no AS.
In Østfoldforskning, she has been involved in the development of preventive environmental protection, from technical environmental analyzes in a company to environmental and resource considerations of products in a lifetime perspective. For four years she was head of department, and she was also acting director for a period in 2003.