Efthalia qualified as a professional teacher with a "Deutsches Staatsexamen" after completing her master's degree at Ruhr-University Bochum. Since 2006, she has been working as a teacher in Europe and South Africa. During her career, she gained a diverse range of teaching experience. She taught at university- and school level, professional language institutes, and her own academy. Efthalia joined King's College in 2018 as a lecturer in German.