He 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.
He had undergone surgery in June 2009 to replace his aortic valve and gallbladder surgery a month later. He had a pacemaker inserted in 1991 and was hospitalized eight years later with a heart attack. In early 2001, he was hospitalized with pneumonia.