Jean Downer was born in Philadelphia on 21 February 1925. She graduated from Philadelphia High School for Girls in 1942 and then worked at the Philadelphia Electric Company and the Supreme Milk Company.
Downer enlisted in the WAVES on her twentieth birthday and in April of 1945 was sent to Hunter College in New York for basic training. She completed hospital corps training at Bethesda Naval Hospital in Maryland and in September 1945 was assigned to St. Albans Hospital in Long Island. In February of 1946 she was transferred to Sampson Naval Base in New York and was discharged from the WAVES in June of 1946.
Downer married Harold John Amann, a Marine she met while in the service, in July 1946. They moved to New York City where she worked as a switchboard operator until they returned to Philadelphia a year later. The couple lived in New Jersey and Buffalo, New York, and had three children together before Amann passed away in 1957. Downer met her second husband, Prescott Downer, while working at a state hospital in New York. After his death, she relocated to Southern Pines, North Carolina.