Marian Robinson, Michelle Obama’s mother and an anchor of the Obama family who moved into the White House and provided stability for her two granddaughters as the young family adjusted to Washington, died on Friday in Chicago. She was 86.

Her death was announced in a statement by Mrs. Obama, former President Barack Obama and other family members. It did not give a cause.

Raised on the South Side of Chicago, Ms. Robinson was known as a down-to-earth matriarch who became an emotional ballast for her daughter and granddaughters, Malia and Sasha, but also for Mr. Obama.

When Mr. Obama became the first Black man to win the presidency in November 2008, he watched the returns alongside his mother-in-law. Their hands were clasped as they watched their future change.

But Mrs. Robinson stayed much the same. “Just show me how to work the washing machine and I’m good,” she said after moving into the White House, the Obamas recalled in their statement.

Mrs. Robinson was never comfortable with the trappings of the White House and much preferred to take her dinner on a TV tray in her third-floor suite. “The only guest she made a point of asking to meet was the pope,” the family said.