Soulié was born in Denmark to a French-Danish father and a Finnish mother. The family moved to Vaasa when Soulié was five years old and he was sent to a Swedish-language school. Soulié attended high school in English. His French improved during an exchange year in Montpellier, France.
Before attending theatre school, she studied contemporary dance at the Salzburg Experimental Academy of Dance in Austria and at the Conservatoire de Région de Montpellier in France.
Sara Soulié is a citizen of both Finland and Denmark.