NEW YORK — As the sun set over a Staten Island community meeting last month, Mayor Michael R. Bloomberg sped through questions about budget cuts, wind power and, inevitably, ferry service. But when a woman thanked him for helping save a popular local Boy Scouts camp, he slipped into unscripted territory.

"I don't know why it just occurred to me," Bloomberg said. "I went up to Boston to see my mother yesterday, who's failing. She's 102 years old and never had a bad day in her life."

Bloomberg, 69, smiling widely, then recounted his own return from summer camp decades earlier, when he told his mother, Charlotte Rubens Bloomberg, that the food at camp was better than home cooking. "Go back! I don't want to be a cook," his mother told him, he recalled.

Charlotte Bloomberg, who died Sunday in her home in Medford, Mass., was a touchstone for her son as he rose from a modest childhood to become one of the wealthiest and most powerful men in the world.

Bloomberg often worked his mother into speeches. Earlier this month, while announcing a plan to offer wireless Internet service in city parks, he used one of his favorite lines, "My mother remembers when the telephone came in," and then last week, when asked about an education issue, he spoke about driving by his elementary school recently while visiting his mother.

And during this spring's round of commencement speeches, the mayor often offered some variation of his favorite piece of parental advice: "Call your mother." It is advice he took to heart — throughout his adult life, he called his mother every day.

His mother nurtured him as he moved from Boston to New York, from working class to billionaire, from anonymous to ubiquitous. In recent months, as Charlotte Bloomberg's health worsened, the mayor took time in meetings to reflect on her life and regale assistants with stories. And he traveled to his mother's home in Medford much more frequently to visit her, said his youngest daughter, Georgina.

"She doesn't have a TV downstairs, so they sit there and talk," she said in an interview last month. "She always asks questions."

Like her son, Charlotte Bloomberg was candid and pragmatic. But she largely shunned the spotlight. When strangers asked if she was related to "the Bloomberg," she sometimes said no, hoping to avoid the attention. When reporters showed up at her doorstep, she told them she had more pressing things to do.

While Michael Bloomberg lavished other family members with multimillion-dollar residences, his mother declined, choosing to stay in the simple two-story home that she and her husband, William, bought more than 60 years ago. When her son sent limousines to pick her up, she sent him back a check. When his private jets arrived, she groaned.

Their relationship was defined in the aftermath of William Bloomberg's death, of heart failure, when his son was 21. Charlotte Bloomberg did not let her husband's sudden health problems slow her down; instead, she devoted herself to learning to use a manual gearshift so she could chauffeur the family.

"She doesn't get upset when things are beyond her control," Michael Bloomberg wrote in his memoir. "She never complains. I think I've inherited that 'just do what you can do and go on to the next thing' approach."

Mary Kay Shartle-Galotto, a college friend of Bloomberg's, recalled his devastation, and resolve, in the days after his father died.

"He said, 'I'm the man of the family now, and I'll always take care of my mother,'" recalled Shartle-Galotto, one of several friends of the Bloomberg family interviewed for this article in recent weeks. "She's really an independent lady and she's been a source of strength for him all his life."

And Sharon E. Baum, a former girlfriend of Michael Bloomberg, said he could be obsessive about making sure he checked in with her. "He was always very attentive to her," she said. "He was a fabulous son."

As Bloomberg rose to prominence on Wall Street, Charlotte Bloomberg was the humbling voice in the back of his mind. After each bit of good news, she would say, "Don't let it go to your head," the mayor recalled in his memoir.

In 2002, she held the family Bible as her son was sworn in. She appeared on the campaign trail (senior centers were her specialty) and accompanied him on trips to Israel in 2003 and 2007.

Ethel Nanes, a friend of Charlotte Bloomberg's for 50 years, said she was proud of her son, especially for his philanthropy, but sometimes seemed skeptical about politics. "I think she wonders why he needs it or why he wants it," Nanes said. "She believes that sometimes people do things to see if they can do things."

Charlotte Bloomberg, who was born in Jersey City, N.J., seemed most comfortable in Medford, where her routine was predictable: services at Temple Shalom, chocolate ice cream at Brigham's, lunch at Legal Sea Foods and piano-playing in the quiet of her home. She participated in a book club, played Scrabble (a game her son avoids) and read two daily newspapers, The Boston Globe and The New York Times.

In Medford in recent years, she was considered something of a wonder, the diminutive centenarian who still ate steak dinners and sat through hours of religious services in a rigid metal chair, although her attendance at services waned along with her health.

She took a keen interest in local politics and education, giving her son's home telephone number to Medford's mayor, Michael J. McGlynn, in case he needed advice. "She walks around like he's just her little boy," McGlynn said.

And Michael Bloomberg, it turned out, was not the only Bloomberg renowned for financial management. His mother, who earned an accounting degree from New York University in 1929, devoted a decade to overseeing the bingo operations at the synagogue, ultimately making the contentious decision to end the games because they were too costly.

"She was able to handle all the pitfalls of the bingo management," said Herb Sandberg, who ran the games with her. "It's like running a little country. Everybody's coming to you with little complaints."

When she was 93, Charlotte Bloomberg was elected as a co-president of Temple Shalom, where a wing is named for her and William Bloomberg, courtesy of a $1 million donation from her son.

Michael Bloomberg returned to Medford for Jewish holidays, and his mother visited New York several times a year. Bloomberg's sister, Marjorie B. Tiven, the mayor's liaison to the United Nations, visited Medford more often, and was Charlotte Bloomberg's frequent companion.

Bloomberg has donated millions in his mother's name, to hospitals, to Hadassah and to the mayor's alma mater, Johns Hopkins University, which will open a children's hospital named for Charlotte Bloomberg next year.

He threw an extravagant party at the Boston Museum of Science for her 100th birthday, complete with Broadway entertainers performing songs rewritten to tell the story of her life.