Elaine K.M. Denniston was born in 1939. She attended Boston Public Schools, graduating from Girls’ Latin School in 1957. She was married to Baron D. Denniston, MD and had two children.
After graduating from high school, Denniston worked at various companies as a clerk and then as a keypunch operator for the New England Life Insurance Company. In 1965 she was hired by Kelly Services, a temporary staffing agency), and in 1966 she was assigned to the MIT Instrumentation Lab (now Draper Laboratory) to keypunch data that programmers wrote for the Apollo Project. Within a few months, Denniston was hired as a permanent employee. During her employment, she keypunched programs, and soon noticed that programmers sometimes omitted a symbol or punctuation in their programs. She frequently had to remind or repeatedly tell programmers to write and submit their programs in a timely manner.
Denniston left the Instrumentation Lab in 1968 because there was no opportunity for advancement. She enrolled in Radcliffe College (now part of Harvard) the following fall. After graduating in 1973 Denniston attended Boston University Law School and practiced law briefly in the private sector. She spent the bulk of her career doing legal and administrative work in various Massachusetts Agencies until her retirement in 2012.