Defne Soyer studied at the Faculty of Law at Paris Panthéon-Sorbonne University between 2013 and 2019, where she was actively involved in human rights and nature protection initiatives. During this period, she interned at WWF.  In 2021, she co-founded “Kocakarı,” a company producing olive oil and natural products, together with her sister, and also briefly worked in investment consultancy.

After obtaining the equivalency of her law degree from Dokuz Eylül University in Türkiye, she completed her legal internship with a focus on environmental law and became a licensed attorney in 2024. She has conducted her work advocating that environmental law should be approached from a nature-centered rather than a human-centered perspective.

She currently works as an independent lawyer specializing in nature protection. In July 2025, following the unjust imprisonment of her father, writer and previous mayor of İzmir Tunç Soyer, she began working in the field of criminal law.