Born Ellen Remsburg, Peck attended University High School, Normal, Illinois and graduated in 1960. She was a high achiever and a standout within her peers, acting as a leader in political, acting and debate arenas. Before becoming famous, and for many years thereafter, Ms. Peck served as an eighth-grade English teacher at Pimlico Junior High School in Baltimore, Maryland where she was known for wearing skirts so short they would not have been allowed on students. She became famous in 1969 for writing "How to Get a Teen-Age Boy, and What to Do With Him When You Get Him," a sort of Sex and the Single Girl for teens. At the time the book was taken seriously, but later Ms. Peck claimed it was written as "humor" and it is usually missing from subsequent lists of her books. The book was quite popular, selling more than 50,000 copies in hard-cover, and promotional materials indicate that she also wrote a syndicated newspaper "advice column for young people." She subsequently wrote another book promoting precocious sexuality, "Sex and Birth Control: a Guide for the Young" (1973), with James Lieberman, M.D.
In 1971, along with William Granzig she wrote "The Baby Trap," one of the first books about the emerging Childfree movement. In 1972, Peck and Shirley Radl founded the National Organization for Non-Parents , an advocacy organization for men and women who choose not to have children. She later wrote several more books on parenthood and was, for a time, a rather prominent childfree advocate, even appearing on the Tonight Show where she exchanged views with Joe Namath.