Marcy was born in Paducah, Kentucky but because her father worked as a field service engineer, the family had to move around a lot. By the time she graduated from high school in Illinois, Marcy had lived all over the United States as well as Switzerland and Iran.
Marcy appeared in All My Children in 1983 but left in 1984 to join Santa Barbara as Eden Capwell, a role which earned her a Daytime Emmy Award for Best Actress. After leaving Santa Barbara, Marcy appeared on Guiding Light as Tangie.
Marcy returned to her role of Liza Colby on All My Children in 1995.
Her other work includes starring roles in several television movies including The Return of Desperado, Bar Girls, Midnight's Child, and Terror In the Shadows.