I am a police reformer and have been since I was promoted to the rank of sergeant in the Boston Police Department in 1975. There were many good cops in Boston in those days, but there was also an insular culture that had some racist, brutal, corrupt and lazy elements. I was motivated to advance in rank to get above the bad actors and to try to do something about them. I had a vision of policing, shared by others of my generation, that looked beyond the stultifying bureaucracy, the curdled cynicism and the sheer indifference that characterized a lot of police work then.

A few years later, as a lieutenant, I helped to develop an early community-policing pilot project in the Fenway neighborhood. Those of us involved wanted to break out of the blue cocoon surrounding policing and work closely with neighborhood residents to protect their communities.

I have carried those experiences and ambitions to the six police departments I have been privileged to lead. In each case, I have worked to change the culture and reach and motivate the officers, connect with the community and reduce crime. My best work in motivating cops was probably in the New York City Transit Police in 1990 and 1991; my best crime fighting, in the New York Police Department in 1994 and 1995; and my best community work, in the Los Angeles Police Department from 2002 to 2009.

The opportunity to come back to New York for a second time awakened the old ambitions, and working with a superlative team at the department and having the unstinting support of Mayor Bill de Blasio, I tried to fold everything I had learned over the years into a reform package that would revitalize a great police agency.