Ruth Bader Ginsburg, who is 85-year-old, went home after falling, but was taken to George Washington University Hospital in Washington after experiencing discomfort during the night.
Tests showed she fractured three ribs on her left side and she was admitted for observation and treatment, according to a statement from the court.
Former Obama aide Valerie Jarrett wrote, "Wishing Justice Ruth Bader Ginsburg a speedy recovery. She is a true force of nature, an extraordinary human being and we need her on the Supreme Court more than ever."
Ginsburg's heath has been the subject of public concern for years as the court's oldest justice has been a prominent progressive voice on the bench.
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She's faced health concerns in the past, including another bout with fractured ribs in 2012.
She had two prior battles with cancer and had a stent placed to open a blocked artery in 2014.
She was appointed to the court by former president Bill Clinton in 1993.
If Ginsburg steps down during the Trump administration, the president will choose another appointee.
Donald Trump has already appointed Neil Gorsuch and Brett Kavanaugh, further tilting the court right.
Actor George Takei said, "Please take care of yourself, Justice Ginsberg. You are our guardian angel. A nation sends its collective wishes for your health and full recovery."
Actress Leslie Grossman offered to donate her ribs to protect the supreme court justice.
"If Ruth Bader Ginsburg needs any of my bones or internal organs I don't need mine," she joked.
