Bacon died in his sleep of congestive heart failure at his Northridge home, according to family friend Stan Rosenfield.
As a reporter for the AP for 23 years and later as columnist for the now-defunct Los Angeles Herald Examiner, Bacon had a knack for befriending A-list celebrities. He palled around with John Wayne, shared whisky with Frank Sinatra, was a confidant of Marilyn Monroe and met eight U.S. presidents.
"They just trusted him," Rosenfield said. "If you look at the people he was friendly with -- Sinatra, Elizabeth Taylor -- these were people who didn't always have friendly relationships with the press."
Bacon accompanied Taylor's physician to her home to break the news of the death of her third husband, Mike Todd, in a plane crash. After filing his story with the AP, Bacon, the only reporter in the house, briefed the mob of reporters outside, Rosenfield said.
Posing as a coroner, he once made his way past a police barricade to get Lana Turner's firsthand account of the fatal stabbing of her lover Johnny Stompanato by her daughter Cheryl Crane.
Operating during an era when press agents posed few restrictions and alcohol flowed freely, Bacon often found himself drinking with the subjects of his stories. Rosenfield said reporters and columnists from competing newspapers were often ordered never to leave an event until Bacon did.
"They had to stay at the party until he left. He would hang out, and get the story at 2 a.m.," Rosenfield said.
After a St. Patrick's Day lunch with John Wayne went into the night, the pair hired a taxi to take them from Los Angeles to see the famed swallows return to Capistrano. After arriving at the Southern California mission in the early morning, a priest told them they were a week early. They took the taxi back to LA.
Years later, Bacon broke the story of Wayne's cancer.
"Jim always made you feel like ... he was a pal looking to hang out," Clint Eastwood once said of Bacon.
He spent 18 years at the Herald Examiner and then went on to write books. He wrote three best-sellers, "Hollywood Is a Four Letter Town," "Made in Hollywood" and Jackie Gleason's autobiography "How Sweet It Is," which he co-authored.
Most recently, he wrote a weekly column about Hollywood's golden years for the glossy magazine Beverly Hills 213, where his last piece appeared in June.
Born James Richard Hughes Bacon on May 12, 1914 in Buffalo, New York, he was inspired to become a journalist by his father, Thomas Bacon, who worked for William Randolph Hearst and Joseph Pulitzer.
In 1942, Bacon joined the AP in Albany, N.Y., as a general assignment reporter, before serving in the Navy during World War II. He rejoined the AP in Chicago in 1946 and moved to the Los Angeles bureau two years later.
Bacon is survived by his wife of 44 years, the former Doris Klein; their children James B. Bacon of Granada Hills, Calif., Thomas C. Bacon of Manhattan Beach, Calif., and Margaret Bacon Smith of L.A.; two children from his first marriage, Roger Bacon and Kathleen Brooks, both of Ventura, Calif.; 15 grandchildren; seven great grandchildren; and a sister, Patricia Wilt of Lock Haven, Pa.
Funeral services will be private.