The three-alarm fire was called in just before 9 a.m. and brought under control within an hour, West Caldwell fire chief Charlie Holden said. He identified Shannon as the only fatality.
Neighbors were able to rescue Shannon's 92-year-old mother, Mildred, through the front door. She suffered what are believed to be non-life threatening injuries, said Acting Essex County Prosecutor Robert Laurino. She was taken to St. Barnabas Medical Center in Livingston, where she was in fair condition.
One neighbor placed a ladder up to the second floor to reach Shannon, but Shannon told the neighbor he was unable to break the window and disappeared into the thick smoke.
"Bill loved baseball, was a true keeper of the game and a one-of-a-kind press box character," said David Lennon, chairman of the New York chapter of the Baseball Writers' Association of America. "Anyone who covered the sport, whether it be in New York, Los Angeles or Chicago, knew Bill from their visits to the ballparks here. It's a terrible loss."
A Hall of Fame voter, Shannon became an official scorer for the American League in 1979 and the National League one year later. In recent seasons he was the senior official scorer for New York Mets and Yankees games.
"He was a unique type of guy," former Mets general manager Omar Minaya said. "He was really a New York baseball personality, and it's a sad day."
Shannon also contributed stories to The Associated Press, covering Columbia football and basketball home games for nearly 50 years, along with many other events.
Jason Zillo, director of media relations and publicity for the Yankees, described Shannon as "a kind and gentle soul, who also happened to be a New York sports legend."
"He loved the game of baseball, immersing himself in its intricacies, nuances and rules," Zillo said. "Most of all, he loved the relationships he built and sustained through his dedication to the sport and his craft. Bill was a Yankee Stadium fixture, and although his name is not as recognizable as some of the greats who played on our fields, his contributions to baseball will leave an enduring and meaningful legacy."
After attending Columbia University and serving in the Army, Shannon was the head of public relations for Madison Square Garden from 1965-73 as it moved into its new building. He also was a longtime assistant on the press staff for the U.S. Tennis Association and a member of the stats crew for New York Jets home games dating to their days as the Titans in the old AFL.
He authored the book, "The Ballparks," a history of major league baseball stadiums, and edited "The Official Encyclopedia of Tennis of the United States Tennis Association."
Shannon also founded the New York Sports Museum & Hall of Fame, which planned to build a sports history museum in New York. He grew up going to New York Giants games at the old Polo Grounds and regaled friends and colleagues with stories about everyone from Leo Durocher to Willie Mays and Marty Marion.
"I used to reference Bill a lot on Fox and when I did Mets games," said announcer Tim McCarver, a former major league catcher. "He was a dedicated and longtime rulesmeister of the game. He was a longtime friend of baseball."
During a rain delay, Shannon might be found holding court in the press dining room, wide-eyed and gesturing enthusiastically while describing an unusual call on the bases or the genesis of the infield-fly rule with his unmistakable, booming voice.
"He was a Runyonesque character from a different era and baseball is definitely worse off without him," Lennon said.
Shannon served on an informal committee set up by Major League Baseball to review and help standardize official scoring rules. Easy to spot with his coke-bottle glasses and sideburns, he eschewed a cell phone or e-mail.
"All of his eccentricities to me were warm and loving ones. There wasn't an evil bone or a malicious bone in his body," said Phyllis Merhige, who supervises official scoring for all 30 big league teams in her role as senior vice president of club relations in the commissioner's office. "He was very passionate about the official scoring that he did for us.
"In baseball, there are certain things you expect to count on. You go to the press box in New York, you expect to see Bill Shannon," she said. "It won't be the same without him."
The cause of the fire is under investigation. It does not appear to be suspicious, according to Jeffrey Cartwright, an assistant prosecutor and director of the office's arson unit.
Funeral arrangements were pending.