Ellyn Lo Fong was born on December 21, 1911 on the Hawaiian island of Oahu. Along with her two older brothers, Ellyn spent much of her childhood helping her parents at the small grocery store they owned in the plantation town of Ewa. After graduating from the newly built Roosevelt High School in Honolulu, Ellyn spent a semester studying at Lingnam University in Guangzhou (previously known as Canton), China before enrolling at the University of Hawaii, where she would go on to receive her bachelor's degree in education. In 1938, after briefly teaching at a school on the island of Kauai, Ellyn left teaching to marry Hiram Leong Fong (1906-2004), a native of Honolulu, Hawaii.

In 1959, when Hawaii became the 50th state, Hiram was elected to the U.S. Senate as both the first senator from Hawaii and first U.S. Senator of Asian ancestry. Hiram and Ellyn, along with their four children, moved to Washington, D.C. where Ellyn became well-known for her hospitality and skill as a hostess for fellow senators and dignitaries. Hiram served as a senator for 18 years, from 1959-1977. Ellyn also gained attention for her work as a Red Cross Volunteer and in 1999 received the Distinguished Service Award from the Organization of Chinese American Women. Ellyn passed away on March 26, 2006 at the age of 94 and is buried along with her husband in Nuuanu Memorial Park in Honolulu, Hawaii.