"He [the latest donor] was incredibly brave to come forward, and give an incredible gift and put his life on the line for someone they never met and change our lives forever," said Binh's father, Michael Wagner, fighting back tears.
Doctors at the news conference said Binh underwent the transplant several weeks ago, and the family had "kept it under wraps."
Binh's twin sister, Phuoc, went through the same surgery on Feb. 10, receiving part of her father's liver to combat the girls' potentially fatal genetic disorder. She is recovering well at home while her sister remains in hospital.
Her mother, Johanne Wagner, said Binh has had some difficulty and misses her sister.
"We're absolutely thrilled that both children are doing extremely well," said Dr. Gary Levy.
He said Binh's donor has also made a complete recovery.
The girls have Alagille syndrome, a genetic disorder that affects vital organs, and would have died without liver transplants.
After Phuoc's surgery, the family appealed for a second donor for Binh. Nearly 500 people contacted Toronto General Hospital to offer parts of their livers for the girl.
Johanne Wagner said she would arrive at the hospital and look up at the room where she imagined the donor was receiving treatment and thank him silently.
"You were in my thoughts," she said. "Thank you for your unselfishness."