Koch was also an outspoken supporter of Israel, willing to criticize anyone, including President Barack Obama, over decisions Koch thought could indicate any wavering of support for that nation.
In a WLIW television program "The Jews of New York," Koch spoke of his attachment to his faith.
"Jews have always thought that having someone elevated with his head above the grass was not good for the Jews. I never felt that way," he said. "I believe that you have to stand up."
Under his watch from 1978-89, the city climbed out of its financial crisis thanks to Koch's tough fiscal policies and razor-sharp budget cuts, and subway service improved enormously. But homelessness and AIDS soared through the 1980s, and critics charged that City Hall's responses were too little, too late.
Koch said in a 2009 interview with The New York Times that he had few regrets about his time in office but still felt guilt over a decision he made as mayor to close Sydenham Hospital in Harlem. The move saved $9 million, but Koch said in 2009 that it was wrong "because black doctors couldn't get into other hospitals" at the time.
"That was uncaring of me," he said. "They helped elect me, and then in my zeal to do the right thing I did something now that I regret."
His mark on the city has been set in steel: The Queensboro Bridge — connecting Manhattan to Queens and celebrated in the Simon and Garfunkel tune "The 59th Street Bridge Song (Feelin' Groovy)" — was renamed in Koch's honor in 2011.
Koch was a champion of gay rights, taking on the Roman Catholic Church and scores of political leaders.
A lifelong bachelor, Koch offered a typically blunt response to questions about his own sexuality: "My answer to questions on this subject is simply, 'F--- off.' There have to be some private matters left."
Rep. Peter King, R-N.Y., called Koch "a true friend and trusted advisor."
"Ed Koch personified the spirit of New York. New York's Mayor For Life is now New York's Mayor for eternity," King said in a statement.
Koch was fast-talking, opinionated and sometimes rude, becoming the face and sound of New York to those living outside the city. Koch became a celebrity, appearing on talk shows and playing himself in movies including "The Muppets Take Manhattan" and "The First Wives Club" and hosting "Saturday Night Live."
In 1989's "Batman," the character of Gotham City's mayor, played by Lee Wallace, bore a definite resemblance to Koch.
When Koch took over from accountant Abe Beame in 1978, one thing quickly became apparent — with this mayor, nothing was certain. Reporters covered him around the clock because of "the Koch factor," his ability to say something outrageous any place, any time.
After leaving office, he continued to offer his opinions as a political pundit, movie reviewer, food critic and judge on "The People's Court."
Koch remained a political force in Albany well into old age. He secured a promise in 2010 from then-aspiring Gov. Andrew Cuomo and a number of state legislators to protect the electoral redistricting process from partisanship — and then vocally protested when Cuomo and others reneged on that pledge two years later.
Even in his 80s, Koch still exercised regularly and worked as a lawyer for the firm Bryan Cave.
At his 80th birthday bash, Bloomberg said Koch was "not only a great mayor and a great source of advice and support to other mayors, he happens to be one of the greatest leaders and politicians in the history of our city."
He had been in the hospital twice in 2012, for anemia in September and then for a respiratory infection in December. He returned twice in January 2013 with fluid buildup in his lungs.