Jack Walsh, 65, a prize-winning sportswriter for The Washington Post who later was an assistant editor with the Washington Post-Los Angeles Times news service, died of cardiorespiratory arrest yesterday at Alexandria Hospital.

Mr. Walsh, who was stricken at his home in Alexandria, worked for the Post from 1947 until he retired in 1980. He covered the Washington Redskins, the Washington Senators, horse racing, harness racing, whatever. His particular passion was the Redskins. But he always managed to convey the idea that while sports are serious pastimes that can excite admiration, wonder, joy and sorrow, they really are there to be enjoyed.

In 1953, Mr. Walsh, who was built like a linebacker, won the top sportswriting award in the Front Page competition of The Washington Newspaper Guild for his story on the retirement of Sammy Baugh, the Redskins' passing great. In 1957, Richard M. Nixon, then vice president, wrote him a letter complimenting him on his coverage of the Redskins-Green Bay game of that year.

In 1964, Mr. Walsh joined the staff of the Post-L.A. Times news service. Sometimes he would write a piece for the newspaper, and his work showed the same knack for telling a story that had marked his career in sports.

An example was his account in 1968 of how he witnessed the landing of the first two Corsair fighter planes to touch down on Funafuti atoll in the Ellice Islands in World War II. Mr. Walsh, who was a combat correspondent in the Marine Corps at the time, said Funafuti was only 750 yards wide and that its highest elevation was two feet above sea level. Some of the permanent inhabitants were descendents of some long-dead O'Brien, lone survivor of a shipwreck.

So monotonous was life on this mere speck situated eight degrees south of the equator in the middle of the wide Pacific that the landing of the first two Corsairs was a big event. Mr. Walsh recalled that the first plane came in perfectly. The second kept bouncing off the new coral airstrip and made a terrible landing.

Two years after the war, Mr. Walsh was on a flight from Boston to Washington that made numerous scheduled stops. The passenger sitting next to him kept coaching the plane in with body English and Mr. Walsh, an outgoing man, engaged him in conversation to calm him down. As luck would have it, the man turned out to be the pilot of the second Corsair on Funafuti.

The odds on that chance encounter, wrote the former harness racing handicapper, were phenomenal.

John J. Walsh was born in Philadelphia. He began his newspaper career on the old Philadelphia Record. During his Marine service in the war, he served two tours of duty in the Pacific. When the Record closed, Mr. Walsh worked briefly for the Atlantic City Race Track. He then moved to Washington and joined The Post.

He was a member of the St. Lawrence Catholic Church in Franconia.

Survivors include his wife, Helen, whom he married on Nov. 11, 1944, of Alexandria; two sons, Christopher, of Alexandria and Tony, of Treasure Island, Fla., and a sister, Mary Mahoney of Albuquerque.