Robert Morgenthau, with four decades of public service as the top federal and state prosecutor in Manhattan, died Sunday at age 99.

Marty Lipton of Wachtell, Lipton, Rosen & Katz, where Morgenthau was of counsel, said he became sick about a week ago and died from his illness. The New York Times reported that his wife Lucinda Franks said he died at Lenox Hill Hospital.

While Morgenthau's handling of some cases drew controversy, his time as Manhattan's district attorney was widely praised by prominent figures in the New York legal world. Crime in New York City fell drastically during his tenure and his office “became the gold standard for any young lawyer who wanted to learn the legal craft,” said Robert Katzmann, who is chief judge for the U.S. Court of Appeals for the Second Circuit, when presenting an award to Morgenthau earlier this year.

Morgenthau was elected as the New York County district attorney in 1974 at a trying time for New York City. Crime was on the rise, white flight was in full swing, and the city's population was slipping after having peaked in 1970.

Central Park Five prosecutor Linda Fairstein with Morgenthau at a news conference in 1988. (AP Photo/Charles Wenzelberg)

While crime eventually fell to historic lows, the tide was slow to turn, and Morgenthau was elected time and time again—often unopposed—to lead the DA's office in the decades that followed. He enjoyed widespread public support, but was not immune to criticism. He served long enough as district attorney to express regret over his office's handling of the Central Park jogger case, where five young, nonwhite men who were accused of assaulting a jogger had their convictions vacated.

On Morgenthau's watch, Manhattan prosecutors handled many high-profile cases: political payoffs by mob boss Anthony “Tony Ducks” Corallo, the shooting of four black youths by white subway gunman Bernhard Goetz, the weapons-possession arrest of hip-hop mogul Sean “Diddy” Combs.

Over the years, Morgenthau's office also prosecuted mob boss John Gotti, who was acquitted on state charges of ordering a hit on a union official, and former Tyco CEO L. Dennis Kozlowski, who was convicted of fraud and larceny in a case seen as an emblem of corporate excess. The office also produced guilty pleas from “Preppie Killer” Robert Chambers Jr. and John Lennon's killer, Mark David Chapman.

In the late 1990s, his state DA's office was winning guilty verdicts in three of four cases. He was the model for DA Adam Schiff on the TV series “Law & Order.”

Morgenthau, who would have been 100 later this month, went to work for Wachtell after leaving office at the end of 2009. He estimated that he oversaw 3.5 million cases in a recent interview with the New York Law Journal.

Lipton, who said he knew Morgenthau since 1956, said the former prosecutor mentored young lawyers at Wachtell after joining as of-counsel. He and his firm hailed Morgenthau for his military service during World War II and for his continued public stands on causes including immigration and gun control after his retirement.

“I knew him as a very concerned person, not just about law enforcement, but about the issues that affect our society,” Lipton said. “He was a voice for reason. He was a voice for democracy. And he was a great patriot.”

Morgenthau, then the U.S. Attorney for the Southern District of New York, with Attorney General Robert Kennedy on the steps of the federal courthouse in New York City on June 14, 1961. (AP Photo)

Morgenthau's career in law began well before he was elected DA. He worked in private practice before being appointed the U.S. attorney for the Southern District of New York in 1961, serving under presidents John F. Kennedy and Lyndon B. Johnson. He ran unsuccessfully for governor of New York in 1962 and 1970.

Morgenthau developed a reputation for targeting white-collar criminals. In 1963, his office successfully prosecuted former Harvard law school Dean James M. Landis for tax evasion.

Ultimately he was forced out as a federal prosecutor in January 1970 by President Richard Nixon.

Ira Lee “Ike” Sorkin, a partner at Mintz & Gold who served as an assistant U.S. attorney in the Southern District of New York in the years after Morgenthau resigned, said he remembered hearing from colleagues that the Nixon administration went so far as to cut off the office's supplies of paper, pencils and notepads in order to pressure Morgenthau to step down.

“It got to the point that Morgenthau finally said, 'I'm not going to hurt this office,' and he resigned,” Sorkin said.

After serving briefly as deputy mayor and making another abortive run for governor, Morgenthau worked for several years as a solo practitioner. In 1974, he defeated Richard Kuh in a special election for Manhattan district attorney.