Photo taken in 2016 shows the Johnsons with Lin Lin, who lived under foster care at the Johnsons' for a long time. Photo provided

Adoption is a key part of Johnson's project, whose ultimate goal is to achieve permanent placement for orphans with a family to call their own.

Dang Xiaohua, born in 1992, suffered from congenital scoliosis and was told that she wouldn't make it to her 18th birthday, as the surgery was expensive and risky to have in China. Physical and mental pain made the girl feel self-contemptuous and she wanted to isolate herself. Aware of Dang's situation, Johnson contacted the best medical institution in the US and paid for the surgery, which cost over 400,000 yuan ($59,256). He also managed to arrange for her adoption by an American family before she turned 14, the upper age limit for adoption. When Dang returned to Taiyuan one and a half years later, she had turned into an outgoing and generous teenager who always had a smile on her face.

Johnson's good deeds changed the lives of many disabled orphans like Dang. According to reports, he has helped over 1,000 orphans in Taiyuan since 2004, of which several hundred received free surgeries. He also raised an 800,000 yuan ($118,543) fund to improve the orphans' living conditions at the Taiyuan welfare institute.

The kindness not only warmed the orphans' hearts, but also touched people around him. Geng always remembers Johnson's words, "Every life needs to be treated with respect, even if he is a disabled newborn."

Johnson, 49 and a father of six, returned to the US in mid-July after nearly 20 years of charity work. It was difficult for his friends in China to say goodbye.

Lu Lu, a former colleague who witnessed Johnson's unreserved commitment to charity in China, still remembers the first time they met 11 years ago.

"Johnson told me in Chinese that it was his hobby to help people, especially disabled orphans," Lu recalled.

"He set a great example for China's charity staff members and also built up an all-Chinese charity team to continue his work. We hope to inherit his spirit and sow the seeds of love across the country," Lu said.