one-day chief; chief for a day
A public relations event where a celebrity or notable person serves as the honorary head of a police station, fire department, or similar organization for one day.
A popular actor served as one-day police chief and called for traffic safety.
A one-day fire chief event was held at the local fire station.
Compound of 一日 (one day) and 署長 (chief of a government office or station).