Koch was a champion of gay rights, taking on the Roman Catholic Church and scores of political leaders.
During the 1977 mayoral campaign against Mario Cuomo, posters that read, "Vote for Cuomo, Not the Homo" mysteriously appeared in some neighborhoods as Election Day approached.
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.