[2] Phelan left Boston after her studies and moved to New York City to pursue a career as a theatre actress.
"[1] Phelan later combined her written monologues with feminist texts and toured with her solo show Corsages and Ketchup in the early 1970s.
[2][3] During her training at Harbor General Hospital she met Roy L. Dennis (1961–1978) and later his mother Florence Tullis, and convinced her to write a script about her son's story.
She then was approached by the head of Universal Pictures at the time, Frank Price, who asked her to write the screenplay for Gorillas in the Mist.
[4] She is known for writing strong women's roles, such as Cher's role in Mask (1985), as a caring and supportive mother towards her son who has a skull deformity, and Sigourney Weaver's part in Gorillas in the Mist (1988), who devotes her life to the study of primates and a strong fighter against illegal poaching in the African jungle.