Former mayor Edward Koch, who presided over New York City during the turbulent late 1970s and '80s and came to personify the city with his wry and outspoken style, died on Friday at the age of 88, his spokesman said.
As mayor from 1978 to 1989, the forceful, quick-witted Koch, with his trademark phrase "How'm I Doing?," was a polarizing figure and the city's constant promoter.
Koch died of congestive heart failure at about 2 a.m. (0700 GMT) at New York-Presbyterian hospital after a year of repeated hospitalizations, the spokesman for Koch said.
Koch, who comes from a family of conservative Jews, was a strong supporter of Israel. In an opinion piece he wrote for The Jerusalem Post in April 2010 Koch declared, "my support for the Jewish state has been long and steadfast."
Stressing the importance of the State of Israel, Koch wrote, "I have also long been cognizant of the fact that every night when I went to sleep in safety, there were Jewish communities around the world in danger. And there was one country, Israel, that would give them sanctuary and would send its soldiers to deliver them from evil, as it did at Entebbe in 1976."
Koch also wrote a regular blog on The Jerusalem Post, where he discussed the US-Israel relations among other topics.
The National Jewish Democratic Council (NJDC) mourned Koch's passing, saying the American Jewish community will not be the same without Koch's vocal advocacy for the US-Israel relationship.
Koch was credited with lifting New York from crushing economic crises to a level of prosperity that was the envy of other US cities. Under his leadership, the city regained its fiscal footing and undertook a building renaissance.
But his three terms in office were also marked by racial tensions, corruption among many of his political cronies, the rise in AIDS and HIV, homelessness and a high crime rate. In 1989, he lost the Democratic nomination for what would have been a record fourth term as mayor.
New York Mayor Michael Bloomberg said the flags at all city buildings would fly at half-staff in Koch's memory.
"In elected office and as a private citizen, he was our most tireless, fearless, and guileless civic crusader," Bloomberg said. "His spirit will live on not only here at City Hall, and not only on the bridge the bears his name, but all across the five boroughs."
Born into a Jewish immigrant family in the Bronx on December 12, 1924, Edward Irving Koch went on to attend City College and later earn a law degree from New York University.
He entered politics in the 1950s in Manhattan's Greenwich Village neighborhood, winning a seat on the city council, and later went to Washington, where he served four terms in the US House of Representatives.
In 1977, he made a second attempt running for mayor of New York City, and proved to be an agile campaigner. To combat rumors he was gay, former beauty queen Bess Myerson began appearing by his side at campaign events.
Koch later admitted the two were never romantically linked. Koch remained a bachelor all his life and refused to answer questions about his sexuality even in his later years.
After two successful terms in office - he was returned for a third term with 70 percent of the vote - Koch's star had began to fade. A corruption scandal involving his ally, Queens Borough President Donald Manes, never implicated Koch, but it damaged his reputation with voters.
Koch's attempt at a fourth term failed when he lost his party's nomination to Manhattan borough president David Dinkins, a man as quiet and deliberative as Koch was bold and abrasive. Dinkins would go on to be the city's first black mayor.
After leaving office, Koch wrote articles on everything from Middle East politics to movie reviews, hosted a radio show and served as a judge on television's The People's Court.
He has remained a formidable figure in New York politics, endorsing candidates and offering political commentary on the local NY1 TV station. He has been a strong ally of New York's current mayor, Michael Bloomberg, and in 2010 he formed New York Uprising, a political action committee designed to fight corruption in state politics.
US President Barack Obama expressed condolences over Koch's death, calling him a "quintessential New Yorker" and an "extraordinary mayor."
"[Koch's] energy, force of personality, and commitment to causes ranging from civic issues to the security of the state of Israel always informed and enlivened the public discourse," he said. "Michelle and I send our thoughts and prayers to Ed’s loved ones, and to the city that survives him."