Marian Robinson, a homemaker from the South Side of Chicago who became the first presidential in-law in generations to live in the White House after her daughter, Michelle Obama, became first lady of the United States, died May 31 in Chicago. She was 86.

The family announced the death in a statement but did not provide a cause.

Mrs. Robinson, who often was called Mrs. R or the “First Grandma,� was the daughter of a painter and a stay-at-home mother and became a stay-at-home mother herself at a time when few African American women could afford not to work.

In a small but comfortable home, she raised her daughter, who pursued a career as a lawyer and health-care executive before becoming first lady, and her son, Craig Robinson, who grew up to become a college basketball coach. In later years, Mrs. Robinson also worked as a bank secretary.

Mrs. Robinson’s husband, Fraser, was a pump worker at the City of Chicago water plant who suffered from multiple sclerosis and died in 1991. He had been a Democratic Party precinct captain, but his wife had little interest in national politics until her son-in-law, Barack Obama, ran for the White House in 2008.

On election night, Obama described his mother-in-law as having been uncharacteristically emotional as she witnessed his historic election as the first Black president of the United States.

“She was sitting next to me, actually, as we were watching returns. And she’s like my grandmother was, sort of a no-fuss type of person. And suddenly, she just kind of reached out and she started holding my hand, you know, kind of squeezing it,� he said in an interview with CBS’s “60 Minutes� shortly after Barack Obama’s victory over the Republican nominee, Sen. John McCain (Ariz.), in November 2008.

“And you had this sense of, ‘Well, what’s she thinking?’ For a Black woman who grew up in the ’50s, in a segregated Chicago, to watch her daughter become first lady of the United States … I think there was that sense across the country. And not unique to African Americans.�

Mrs. Robinson’s children often described her as a woman who spoke her mind and cherished her privacy. She sought to maintain those traits after agreeing to move with her daughter’s family into the White House.

“They’re dragging me with them, and I’m not that comfortable,� she told an interviewer when she left home, “but I’m doing exactly what you do. You do what has to be done.�

The decision drew widespread attention. Mrs. Robinson was the first presidential mother-in-law to live in the White House since Elvira “Minnie� Doud, Mamie Eisenhower’s mother.

Mrs. Robinson’s role was helping granddaughters Malia and Sasha Obama adjust to life in the Washington bubble and maintain normalcy.

She rode to school with the girls in Secret Service SUVs and tucked them in at night when their parents’ schedules kept them from home.

“One of my biggest blessings is getting to see my granddaughters grow up before my eyes. My job here is the easiest one of all: I just get to be Grandma,� Mrs. Robinson wrote in a 2012 essay published in Essence magazine.

During the time that she lived in the White House, Mrs. Robinson rarely gave interviews and appeared publicly with the Obamas only on holidays and at some cultural events, often when her granddaughters were present.

“If somebody’s going to be with these kids other than their parents,� she once said, “it better be me.�

Marian Lois Shields, one of seven siblings, was born in Chicago on July 30, 1937. After all their children were born, her parents separated.

Marian attended two years at a teachers’ college but did not complete the program for financial reasons, her son wrote in a memoir. In her early 20s, she married Fraser Robinson and stressed the importance of education to her children, both of whom graduated from Ivy League schools.

“She taught us that you can be open and honest about your own shortcomings and it doesn’t necessarily mean your kids are going to adopt them,� Michelle Obama once said.

The Robinson family was skeptical when Michelle brought Barack Obama home to introduce him; they had met at the Chicago law office of Sidley Austin and began dating in 1989.

Michelle had been career-focused and showed little interest in settling down. But after their marriage in 1992, the large Chicago-based family brought him into its fold. Barack had few relatives nearby, and the Robinsons threw his birthday parties and became the family with whom he celebrated holidays.

Barack Obama said Mrs. Robinson was an unsung hero in his political trajectory. Had she not quit her job to help care for her granddaughters, Michelle Obama might not have felt comfortable taking on the travel required to support her husband’s presidential campaign.

Mrs. Robinson continued to live in the Chicago walk-up that she and Fraser had shared until moving to the White House. There, she lived on the third floor — one level up from where “Michelle’s family� lived.

Mrs. Robinson described herself as being like most grandmothers. She teased her daughter about her strict rules for Malia and Sasha, including limited television-watching and early bed times.

“I’ve heard [Michelle] say, ‘Mom, what are you rolling your eyes at? You made us do the same thing,’� Mrs. Robinson once told the Boston Globe. “I don’t remember being that bad. It seems like she’s just going overboard.�

Mrs. Robinson described her approach to grandmothering as: “I do everything that grandmothers do that they’re not supposed to.�

“I have candy, they stay up late … they watch TV as long as they want to, we’ll play games until the wee hours,� she said.

In addition to her daughter and son, survivors include six grandchildren.

Along with her deep involvement with her family, Mrs. Robinson maintained varied interests. She was in her 50s when she took up running and won gold in the 50-meter and 100-meter races at the 1997 Illinois Senior Olympics. She stopped running after an injury.

“If I can’t do it fast, I’m not doing it,� she told Oprah Winfrey’s magazine in 2007. “You don’t run just to be running — you run to win.�

She had not traveled abroad before her son-in-law was elected president and seemed to like tagging along on the first family’s official overseas visits. When asked once whether she was enjoying her life in Washington, Mrs. Robinson told Essence, “I really am. You want to know why? Because my children are good parents. It makes it very easy to be a grandmother when your children are good parents.�

Mrs. Robinson built a busy social calendar that included trips to casinos in Las Vegas and concerts in Washington. At the same time, her low profile gave her a level of anonymity that allowed her to travel without a security detail. If someone recognized her as the mother-in-law of the president, she would often say, “I get that a lot.�