Michael J. O’Neill, a former editor of The Daily News in New York who directed its breathless coverage of the “Son of Sam” serial killer, then became a strong national voice for responsible media behavior, died on Tuesday at his home in Scarsdale, N.Y. He was 89.

The cause was complications of pulmonary fibrosis, his family said.

When Mr. O’Neill became executive editor of The News in 1974, it was the nation’s largest general-interest newspaper, with a daily circulation of about two million. (It is now under 600,000.) The next year, it published the headline many deem the most famous in American journalism: “Ford to City: Drop Dead.” It referred to President Gerald R. Ford’s denial of federal assistance to save New York City from bankruptcy. Mr. Ford never actually said “drop dead,” however well the phrase captured his point, and thought the headline cost him the White House....