Ruth V. Hemenway was born in 1894 in Williamsburg, Massachusetts, the third of five children of Elijah and Ella (Shumway) Hemenway. She was raised on her father's 100 acre farm and intellectually nurtured by her mother who was a teacher. Following graduation from Williamsburg High School in 1910, in order to save enough money to go to medical school, she taught in a one-room schoolhouse in Conway, Massachusetts, and later in the Williamsburg-Searsville School. She earned her way through Tufts Medical School, graduating in 1921, and by her junior year had decided to practice medicine in China. After interning at the Women's Medical College in Philadelphia and at the Pennsylvania State Hospital in Allentown, she realized that the best opportunity to reach that goal was to become a Christian missionary.

In 1924 she accepted support from The Grace Harris Memorial and an appointment from the Methodist Women's Board of Foreign Missions to direct a 100-bed hospital for women in Mintsing, Fukien, China. She remained there for thirteen years, except for one year when she was surgeon at a Methodist hospital in Nanking. Hemenway entered China at a time of great political unrest with political parties, warlords, and bandits battling for control. Although encouraged by the Chinese unification under Chaing Kai-shek in 1928, she continued to believe that the hope of China's future lay in the rural communities where eighty percent of the people lived. She established clinics, health facilities, and paramedical teams; and introduced programs in elementary hygiene and science. She was especially interested in improving the health of women and mothers, establishing prenatal counseling and general child care. Although she grew increasingly alienated from the goals and practices of organized Christianity, she continued her work with the firm belief that with or without the aid of Christian missionaries, the combination of modern knowledge and ancient Chinese traditions would produce a new China. When the Japanese invaded China in 1937, she went to Chunking, then the capital, to head the obstetrical department of a hospital sponsored by Syracuse University. She stayed in Chunking until 1941 when she returned to the United States on furlough.

Hemenway spent a year of study at the Hague Maternity Center in Jersey City, New Jersey, and later took a position on the staff at Christian Hospital in Sharon, Pennsylvania. Although she had every intention of returning to China, due to her mother's failing health, she remained in Williamsburg where she continued her medical practice. Hemenway was an avid watercolorist whose paintings of China were exhibited locally. She adopted four Chinese children. Ruth Hemenway died in Northampton, Massachusetts, July 9, 1974, at the age of 80.