"I'm not the type to get ulcers," he wrote in "Mayor," his autobiography. "I give them."
When President George W. Bush ran for re-election in 2004, Koch, a Democrat, crossed party lines to support him and spoke at the Republican convention. He also endorsed current Mayor Michael Bloomberg's re-election efforts at a time when Bloomberg was a Republican. Koch described himself as "a liberal with sanity."
In a statement Friday, Bloomberg said the city "lost an irrepressible icon" and called Koch its "most charismatic cheerleader."
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 near-financial ruin 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.