Manhattan District Attorney Robert Morgenthau will not seek re-election, after serving in the office for 35 years.

The 89-year-old city law enforcement official, who once told NY1 he was "too old to retire," has decided not to run for another term this upcoming fall.

"I decided I wouldn't try to push my luck any further. Quit while I'm ahead. I don't know what I'll do," said Morgenthau at a press conference this afternoon.

Morgenthau said he was in good health and did not view his decision as a retirement.

“I got an email from my older brother saying it’s a bad time to be looking for a job. But whatever I do, I’ll be supporting this office in any way I can,” he said.

Clearly age was no obstacle for Morgenthau, who won his first election as district attorney back in 1974, ultimately becoming the longest-serving Manhattan District Attorney in history – winning re-election an astounding eight times.

The veteran prosecutor was a vocal opponent of the death penalty, but a respected crime fighter, while also prosecuting high-profile cases, like subway vigilante Bernhard Goetz, the so-called "preppie killer" Robert Chambers, rapper Sean "Puffy" Combs, and former Tyco head Dennis Kozlowski.

But Morgenthau said all cases are equally important.

"The ones that you just say, 'what an outrage,' there are other outrageous cases out there," he said. "Don't put too much focus on a case that the media and public quite properly is interested in, and neglect other cases where a life has been taken, and are just as important."

City officials today sang his praises.

“He has had an unmatched career, not only in longevity but also in service to the people of New York County,” said Police Commissioner Ray Kelly. “He truly is a legend and he’s been a major force in law enforcement throughout the country, and we all know about his international reach as well. He’s just an icon.”

“Robert Morgenthau is a giant, someone who lifted the reputation, the level of excellence of district attorneys, not just here in New York City but across the state and throughout the United States,” said Brooklyn District Attorney Charles Hynes.

Morgenthau was appointed United States Attorney in Manhattan in 1961 by his friend, President John F. Kennedy. Morgenthau remained in the U.S. Attorney's office until 1970, where he gained the reputation of an avid prosecutor of organized crime tax fraud and political corruption.

This year's race for Manhattan district attorney is suddenly wide open.

Former Judge Leslie Crocker Snyder, who challenged Morgenthau in 2005, is running once again.

"I've had an increasingly, vigorously proactive and progressive agenda for New York and I look forward to sharing that with the voters," said Snyder.

Citizens Crime Commission President Richard Aborn is also eyeing the job.

"I decided back in September. I had spoken with people four or five months before that and people were incredibly respectful and incredibly encouraging," he said.

Other possible candidates include Morgenthau's top aide and Assistant District Attorney Daniel Castleman, Former Deputy Mayor Randy Mastro, Manhattan State Senator Eric Schneiderman, former State Senator Catherine Abate and former Assistant District Attorney Cyrus Vance Jr.

Insiders say Morgenthau may throw his support behind Vance.