He graduated from Yale University in 1878 and the New York College of Physicians and Surgeons in 1882 and practiced as a medical doctor in Cleveland, Ohio for three years.

One of American missionaries for Japan, Robert S. Maclay, visited Korea in 1884 to seek permission from the king Gojong to start Methodist mission work, and he was granted limited permission to establish a Methodist mission only for educational and medical work.

William Scranton arrived in Japan in February 1885 with his wife, Loulie Wyeth Arms, and his mother for mission in Korea.

The dispensary was expanded in 1886 to include 5 wards, and the king Gojong gave it the name Si Pyung Won (Korean: 시병원; Hanja: 施病院), meaning "the universal relief hospital.

"[2] After experiencing struggles with Merriman C. Harris,[clarification needed] Scranton resigned from the Methodist mission in 1907[3][4] and became Anglican.