[1] Zavala Giler obtained an interest in criminal law and human rights from his grandfather, of whom he has stated was a large influence in his life.

[2] In 2010 Zavala Giler started working as a special assistant to the registrar, then Silvana Arbia.

[1][2] On 10 February 2023 he was elected Registrar by an absolute majority of the judges of the ICC in a secret ballot.

[7] Zavala Giler stated that his goal as registrar was to: "build the ICC as a model of modern public administration that ensures effectiveness and safeguards accountability" and he saw the court's legitimacy being continuously at stake as the largest challenge.

[6] In May 2023 Zavala Giler together with ICC President Piotr Hofmański met with Ukrainian President Volodymyr Zelenskyy, who praised the court for its work in relation to the International Criminal Court arrest warrants for Vladimir Putin and Maria Lvova-Belova.