Piercy was born in Detroit, Michigan, to a Bert (Bunnin) Piercy and Robert Piercy. Upon graduation from Mackenzie High School, Marge became the first in her family to attend college, studying at the University of Michigan. Winning a Hopwood Award for Poetry and Fiction (1957) enabled her to finish college and spend some time in France. She earned a M.A. from Northwestern University. Her first book of poems, Breaking Camp, was published in 1968.
An indifferent student in her early years, Piercy developed a love of books when she came down with rheumatic fever in her mid-childhood and could do little but read. "It taught me that there's a different world there, that there were all these horizons that were quite different from what I could see".
Piercy was a significant feminist voice in the New Left and SDS.