The New York City Police Commissioner is the head of the New York City Police Department

New York City Police Department

The New York City Police Department , established in 1845, is currently the largest municipal police force in the United States, with primary responsibilities in law enforcement and investigation within the five boroughs of New York City...

, appointed by the Mayor of New York City

Mayor of New York City

The Mayor of the City of New York is head of the executive branch of New York City's government. The mayor's office administers all city services, public property, police and fire protection, most public agencies, and enforces all city and state laws within New York City.The budget overseen by the...

. Governor Theodore Roosevelt

Theodore Roosevelt

Theodore "Teddy" Roosevelt was the 26th President of the United States . He is noted for his exuberant personality, range of interests and achievements, and his leadership of the Progressive Movement, as well as his "cowboy" persona and robust masculinity...

, in one of his final acts before becoming Vice President of the United States

Vice President of the United States

The Vice President of the United States is the holder of a public office created by the United States Constitution. The Vice President, together with the President of the United States, is indirectly elected by the people, through the Electoral College, to a four-year term...

 in March 1901, signed legislation replacing the Police Board and office of police chief with a single police commissioner. The Commissioner is a civilian administrator appointed by the Mayor of New York City. There is a separate position of Chief of Department, the holder of which serves as the senior sworn uniformed member of the force.
Prior to 1901, the NYPD was run by a board of four to six commissioners that jointly ran the department.