Former Mayor Rudolph Giuliani is hailing Nicholas Scoppetta as a "great New Yorker" following the death of the long-time corruption fighter and agency head.

Scoppetta, who led New York City’s fire department and child-welfare agency, and spent many years as a prosecutor and corruption-fighter, died Thursday after a battle with cancer.

• Watch Budd Mishkin's 2010 "One on 1" profile of Nicholas Scoppetta

Scoppetta wore many hats across more than four decades of public service, but he is perhaps best known for his role on the Commission to Investigate Alleged Police Corruption, known as the Knapp Commission, and as a prosecutor in a later federal investigation.

Scoppetta convinced NYPD Detective Robert Leuci to cooperate in the investigations, a case that became popularized in the book and movie "Prince of the City."

He gained prominence again with two subsequent high-profile roles in city government – first as Giuliani’s appointee to head the city’s new Child Welfare Administration, and later as the city’s 31st fire commissioner, holding that post under Mayor Michael Bloomberg from Jan. 1 2002, until 2010.

"Nick was a close friend for over 40 years and for many of those years as a colleague in the U.S. Attorney’s Office and in city government." Giuliani said in a statement. "He was a great New Yorker and a truly good man."

Scoppetta was born in 1932, to struggling Italian immigrants on the Lower East Side.

He attended Seward Park H.S. served in the Army, and graduated from Bradley University and Brooklyn Law School.

Scoppetta entered public service as an investigator for the Society for the Prevention of Cruelty to Children, and he then became a prosecutor under legendary Manhattan District Attorney Frank Hogan.

He served as city Commissioner of Investigation under Mayors John Lindsay and Abraham Beame, and later served as Deputy Mayor for Criminal Justice under Beame.

Scoppetta was a prominent defense attorney with his own practice for more than a dozen years before being named by Giuliani to oversee the city’s troubled child welfare agency.

At the time of that appointment, Scoppetta revealed that when he was a young boy, his parents sent him and two brothers to city foster care for a time. They lived in a shelter on E. 104th St and at a group home in the Bronx. He later credited the experience with saving his life.

Scoppetta was 83 years old.