NEW YORK (CBSNewYork/AP) — Bill Bratton will be stepping down as New York City’s 42nd police commissioner next month to reportedly take a job in the private sector. Here’s a look at his life and police career.

Bratton, a U.S. Army veteran who served in Vietnam, was inspired to become a cop at age 9 when he took out a library book called “Your Police,” which is about policing in New York City. He started his police career in 1970 as a beat cop in the Boston Police Department, where he later became commissioner.

NEW YORK, NY - DECEMBER 05:  New York Mayor-elect Bill de Blasio (R) stands with Bill Bratton, holding a library book called "Your Police," after having been named to lead the New York Police Department on December 5, 2013 in New York City.  Bratton was police commissioner in New York in the mid-1990s and had been considered a front-runner for the job, He will return to a city that is experiencing historically low crime rates.  (Photo by Spencer Platt/Getty Images)

Bill Bratton, holds a library book called “Your Police,” after having been named to lead the New York Police Department on December 5, 2013. (Photo by Spencer Platt/Getty Images)

He holds a Bachelor of Science degree from Boston State College and is a graduate of the FBI National Executive Institute and the Senior Executive Fellows Program at Harvard’s John F. Kennedy School of Government.

This was his second stint as head of the NYPD. He was previously police commissioner under former Mayor Rudy Giuliani from 1994 to 1996, during which time he emphasized the broken-windows theory of police work: that criminals who commit small crimes, such as vandalism, also commit more serious crimes. The two frequently fought over who deserved the lion’s share of the credit for a decline in crime in the city and Bratton resigned after two years. He returned to the post in 2014 to serve under Mayor Bill de Blasio.

PHOTOS: Bratton Resigns

Bratton helped spearhead the use of CompStat, a data-driven system of tracking crimes that allows police to better allocate their resources to high-crime areas. The real-time system is still used today.

Bratton is married to CBS contributor Rikki Klieman and has one son, and two grandchildren.

(TM and © Copyright 2016 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2016 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)