Etienne is the former Deputy Prime Minister (from 2013), Minister of Economy (from 2012), Minister of Health (from 2018), Minister of Internal Security and Minister of Defense (from 2013) of Luxembourg. He held those various positions between 2012 and 2020, being a member of the Luxembourg Socialist Workers' Party (LSAP). He has previously filled several positions as a senior civil servant, such as a research assistant at the European Parliament in Brussels, economist for the LSAP parliamentary group in the Chamber of Deputies and project leader with NATO in Brussels. He also served as a government advisor responsible for various Directorates. Etienne has a degree in commercial and financial sciences from the Institut catholique des hautes études commerciales (ICHEC) in Brussels and Greenwich University in London (1995).