This was decided in consultation with a representation of the municipal council of Opmeer on April 16, 2025. The appointment is effective from May 27, 2025, until the vacancy for the mayor is filled.

Wiersema is currently a manager at the National Coordinator for Counterterrorism and Security and the National Crisis Center. Previously, Wiersema was a manager and advisor at the municipality of Amersfoort. From 2014 to 2018, he was the chairman of the PvdA Amsterdam.