Sarah left Children's Hospital of Philadelphia Tuesday morning and returned to her family's home in Newtown Square.
Her mother, Janet Murnaghan, posted a message on Facebook yesterday announcing Sarah would be going home.
The Delaware County 11-year-old received two sets of lungs this summer as she struggles with the effects of end-stage cystic fibrosis.
In the Facebook post late Monday, Janet wrote that she and her daughter had "cried tears of joy."
"We entered CHOP on Feb. 19, more than six months ago. I never could have imagined the journey that lay in front of us," Murnaghan wrote in the post, thanking God, Sarah's donors and all those who supported the family.
Sarah received the two lung transplants after a federal judge intervened in her parents' lawsuit challenging national transplant rules that put her at the end of the waiting list for adult lungs.
The news capped days of upbeat progress reports from the Murnaghan family.
On Sunday, Murnaghan said her daughter was taken off oxygen, although she still gets support from a machine that helps her to breathe, and had started to walk with the aid of a walker, even venturing outside.
"My sister pointed out that today is our Mom's birthday - she died 11 years ago," Murnaghan wrote Saturday on her Facebook page. "And today is the first day Sarah has not needed any supplemental oxygen. Miracles from heaven!!!"
Family spokeswoman Tracy Simon said Sarah's recovery is now focused on building her muscle strength so she no longer has to use a breathing tube. She said Sarah recovered from a case of pneumonia that stemmed from the tube.
Sarah's first set of adult lungs failed after a June 12 transplant. A second set was transplanted three days later.
Her parents sued to change a national transplant policy that put her at the bottom of the adult list for patients 12 and older. After the federal judge intervened, the Organ Procurement and Transplantation Network - the private nonprofit group that manages U.S. organ allocation - added Sarah to the adult list.
The case raised questions among some health specialists and medical ethicists about how organ donation rules are developed and under what circumstances they might be disregarded.
Ron Todt of the Associated Press contributed to this report