The 7-year-old labrador-chow mix was born without front legs.
The puppy and her siblings, also deformed, were rejected by their mother. But Reuben Stringfellow, then 17, came across the tiny animal and brought it home.
He and his mother Jude, an English professor, had to carry the puppy, which they named Faith, for the first few months of her life. But eventually, with patience, and lots of peanut butter as a lure, Faith learned to walk on her two hind legs.
Seven years after her birth, the little yellow dog zips around crowded shops, bustling along with confidence.
Since her first steps in March, 2003, Faith has been a regular guest on US talk shows. She has also become a symbol of hope for injured soldiers.
Ms Stringfellow, who has become a motivational speaker and runs a website devoted to her tiny dog, gets more than 200 letters and emails a day.
Fans of the little dog say she provides inspiration.
“Faith has shown me that different is beautiful, that it is not the body you are in but the soul that you have,” Jill Salomon of Montreal, Canada, wrote on the website.
Ms Stringfellow regularly brings Faith to veterans’ hospitals across the US to provide hope to disabled soldiers, a mission inspired by her son’s service in the US army in Iraq.
Ms Stringfellow told AP that during a recent visit to McChord Air Force Base and Fort Lewis in Washington, the dog brought cheer to soldiers heading off to war, and to those recently returned.