John Denson, 79, a retired editor and reporter who had held high posts with newspapers and magazines in Washington and New York City, died of a heart ailment Nov. 5 in a nursing home in West Palm Beach, Fla. He lived in Florida.

Mr. Denson worked for Newsweek magazine for eight years, and was its editor from 1956 to 1961. He was editor of the old New York Herald Tribune from March 1961 to October 1962. Also during the 1960s, he was executive editor of the old New York Journal American and editor of the Los Angeles Herald Examiner.

From 1927 to 1929, he was a member of the Washington bureau of the New York Herald Tribune. He then worked in New York for the World and the World-Telegram. He returned to Washington in 1934, and for the next two years, was an assistant managing editor of The Washington Post.

During World War II, he worked for CBS and Time magazine. After the war, he was an associate editor of Fortune magazine and managing editor of the old Collier's magazine.

Mr. Denson was a native of Arcadia, La., and began working as a reporter in the midwest when he was 16 years old. His last job was as cofounder and editor of the old New York Trib, a daily journal started in 1978 that sought to be literate and politically moderate. The paper failed.

Mr. Denson's wife, the former Katherine Alvord, died in 1977.

He leaves no immediate survivors.