Tisch, 43, the Harvard-educated scion of a wealthy New York family, has worked for the city for 16 years, holding leadership roles in several agencies. As sanitation commissioner, she became TikTok famous when she declared in 2022, "The rats don't run the city, we do."

Tisch, 43, who until days ago was sanitation commissioner, takes over a department that has had tumultuous leadership changes.