Francis Sleeper, a business reporter for the Portland Press Herald, Maine Sunday Telegram and Evening Express for nearly four decades, died Friday in Portland. He was 79.

Sleeper, who died after a long struggle with prostate cancer, was a quirky, old-fashioned and hardworking newsman who wielded enormous influence in the local business community during the 1950s and 1960s.

“When Frank Sleeper spoke on matters of business back then, everybody listened,” said Dennis Twomey, who joined the news staff as a reporter in 1967. “He was kind of a legendary fixture among young reporters.”

Sleeper carried a foot-thick stack of papers around with him, and his desk was typically piled high with them. “You couldn’t even see Frank behind the desk,” said Louis Ureneck, a former editor, who also recalled that it was not unusual to find Sleeper writing stories in the newsroom at 4 a.m.

A Harvard University graduate, Sleeper earned master’s degrees from American and Princeton universities and studied in Egypt for two years on a Fulbright Scholarship before being hired as a reporter for the Portland Newspapers in 1953.

From 1958 until last November, Sleeper was the Maine correspondent for Time, Life, Sports Illustrated and Fortune magazines. A boxing fan, he was asked to cover the heavyweight title fight between Cassius Clay, who later became Muhammad Ali, and Sonny Liston in Lewiston. Before the bout, Sleeper interviewed Clay during a short jog they took together along the Maine Turnpike.

Over the years, Sleeper freelanced for various publications, and after his retirement he wrote several books about Maine history.

Survivors include sons Bruce, of Portland, and Eric, of Princeton, N.J., and five grandchildren.

A funeral Mass will be celebrated Wednesday at St. Alban’s Episcopal Church in Cape Elizabeth.