About the size of a 3-inch tube of penne pasta, it was implanted April 9 in a nine-hour procedure.
Early signs indicate the windpipe is working, her doctors announced Tuesday, although she is still on a ventilator. They believe she will eventually be able to live at home and lead a normal life.
"We feel like she's reborn," said Hannah's father, Darryl Warren.
He choked up and his wife, Lee Young Mi, was teary-eyed at a news conference Tuesday. Hannah did not attend because she is still recovering from the surgery. She developed an infection after the operation but now is acting like a healthy 2-year-old, her doctors said.
About one child in 50,000 worldwide is born with the windpipe defect. The stem-cell technique has been used to make other body parts besides windpipes and holds promise for treating other birth defects and childhood diseases.
The operation brought together Paolo Macchiarini, an Italian surgeon based in Sweden who pioneered the technique; a pediatric surgeon at Children's Hospital of Illinois in Peoria who met Hannah's family while on a business trip to South Korea and helped work out a waiver of the costs, likely hundreds of thousands of dollars; and Hannah - born to a Newfoundland man and South Korean woman who wed after he moved to that country to teach English.
Holterman said Hannah would likely need a new windpipe in about five years, as she grows.
She is not yet able to eat normally, but doctors let her have her first taste ever of food - a few licks on a lollipop.
Her father said she already has discriminating taste: She prefers chocolate Korean lollipops to the American kind.