After her schooling Motoc studied law at the University of Bucharest. After a master's degree in law at the University Paul Cézanne Aix -Marseille III and received his doctorate in international law to a topic. At the Jean Monnet Institute of the University of Paris-Sud habilitation followed, they also acquired the title of Doctor of Philosophy at the Institute of Philosophy of the University of Bucharest. Motoc was a member and President of the UN Sub-Commission on the Promotion and Protection of Human Rights. She was UN special rapporteur for human rights in the Democratic Republic of Congo and the United Nations Special Rapporteur on the recent human rights violations. In this role, she drew particular attention to violence against women and children. She continues to act as Arbitrator and Mediator in the International Centre for Settlement of Investment Disputes.
She is a member of the Human Rights Committee of the United Nations. In addition, she is a professor at the University of Bucharest, where she teaches courses on international law, human rights and European law. She teaches as a guest lecturer at several universities, including NYU, Yale University, European University Institute, Florence and the UN University in Tokyo.
In 2010 she was appointed as a judge of the Constitutional Court of Romania. On December 18, 2013, she was appointed judge at the European Court of Human Rights.
Motoc is married to the current Romanian Ambassador to the EU Mihnea Motoc. The couple has a son.