Spencer Hoyt, who was called Heo Ik-du, was born in 1895 in the U.S. state of Ohai. He graduated from the University of California Medical School and became a doctor. His wife, Nell Henderson Hoyt, was born in California, USA in 1900. The two married in the United States and visited Korea on September 1, 1922, as missionaries to the Northern Presbyterian U.S.A.

Earlier, he was appointed as a doctor at Dongsan Christian Hospital on behalf of the Smiths, helped Fletcher to conduct medical missions, and was a great help to Fletcher.

Hoyt treated using the best sterilizer and X-ray imaging equipment, but because there was no place to install X-ray imaging equipment, he installed it by setting up oil stand in the women's hospital room. I learned Korean with the help of Seo Bo-gi, Fletcher's assistant. In addition, he frequently used Mr. Seo Bo-gi to provide medical treatment and later trained him to become a radiologist.

He liked Dongsan Christian Hospital very much because it had talented assistants and good pharmacies and medicines available, and while working at the hospital, he took care of patients with his identity as a mission hospital and worked hard to evangelize.

Hoyt's wife Nell returned to the United States on vacation in 1927 due to poor health, but the Hoyt couple were unable to visit Korea again due to health problems. Shortly after returning home, Hoyt was called by God for a sudden heart attack. His wife, Mrs. Hoyt, came to Korea alone and stayed for a while, and since many people had an affection toward Hoyt, many people expressed condolences from inside and outside of Dongsan Christian Hospital for him.

Spencer Hoyt (5th from the right side of the first row) in a leaflet introducing Dongsan Christian Hospital and Aerakwon, 1925