Jessica S. Tisch, the head of the city’s Sanitation Department, has been named the new commissioner of the New York Police Department, Mayor Eric Adams announced on Wednesday.

Mr. Adams announced Ms. Tisch’s appointment at a news conference about the budget. His decision follows the resignation of Edward A. Caban on Sept. 12 and the subsequent appointment of Thomas Donlon on an interim basis.

The announcement came as a surprise after months of speculation over who would lead the Police Department permanently.

Mr. Adams, who was indicted in September on federal corruption charges, and other City Hall officials pressured Mr. Caban to step down. Federal agents seized his cellphone in one of five criminal investigations that have upended City Hall.

Ms. Tisch has run the Sanitation Department since April 2022, pushing for clean streets as the city emerged from the disruption of the coronavirus pandemic and becoming internet-famous as a scourge of rats. Before that, she held positions throughout city government, including in the Police Department as a deputy commissioner for information technology. She has a reputation as a demanding boss who is not afraid to rethink how government works.

The new commissioner is part of a prominent New York family that owns the Loews Corporation conglomerate and co-owns the New York Giants.

Ms. Tisch holds three Harvard degrees, including an M.B.A. and a law degree. She will take over a department that has about 55,000 civilian and uniformed employees, and that has been closely linked to the mayor, a former police captain who appointed several associates to top positions.

Ms. Tisch’s appointment marks an end to the brief tenure of Mr. Donlon, a Bronx native with an extensive background in federal law enforcement, who has led the department as Mr. Adams navigated the scandals engulfing City Hall.

This is a developing story and will be updated.