During World War II, her family escaped France, moving to Rio de Janeiro, Brazil, via a short stay in Portugal. This journey inspired the creation of her piece, My Brazil. In April 1941, her family left Brazil to settle in New York, where Rosenthal would later graduate from the High School of Music and Art.
After settling back in New York in 1953, her social circle included John Cage, Merce Cunningham, Sari Dienes, Robert Rauschenberg and Jasper Johns. She was introduced to Zen Buddhism and Asian philosophy by Cage. She soon grew an interest in martial arts (kung fun, tai chi, karate) and started training in them.
In 1955, she moved to California, and became involved with the art scene surrounding the Ferus Gallery. That year she created the experimental "Instant Theatre," within the Cast Theatre (now named El Centro Theatre), performing in and directing it for ten years. She was a leading figure in the L.A. Women's Art Movement in the 1970s and co-founded the Womanspace Gallery, a cooperatively run gallery devoted to work by female artists, in 1973. She is considered one of the "first-generation feminist artists," a group that also includes Mary Beth Edelson, Carolee Schneeman, and Judy Chicago. They were part of the Feminist art movement in Europe and the United States in the early 1970s to develop feminist writing and art. By 1975, she had written, created, directed and acted in more than 30 full-length performances in the United States and Europe. Rosenthal began teaching classes in performance in 1979.
The Others (1984) was her landmark show in which the stage was shared with forty-two animals ranging from goats, snakes to monkeys; all animals had a printed bio and were treated as equals. In 1987, she was invited to design a piece specifically for the international art fair, Documenta 8, occurring in Kassel, West Germany. Her original piece for this was Rachel’s Brain, with music by Stephen Nachmanovitch. Rachel's Brain dealt with brain research findings,intellectual history and hubris. Alan M. Kriegsman, a Writer for the Washington Post, describes her performance as notably magnetic, skillful and sufficient to keep you raptured.
Rosenthal was the Director of the Rachel Rosenthal Company which she formed in 1989 in Los Angeles, California. The company's repertoire deals with themes such as environmental destruction, social justice issues, animal rights, earth-based spirituality, in a Hybrid form that combines voice, text, movement, music, video projection, and elaborate theatrical costuming, set design, and dramatic lighting, ultimately challenging the rigid boundaries that have traditionally separated performance art from theater. She is an advisory board member of the New Museum of Contemporary Art in New York.
In 1990, Rosenthal premiered Pangaean Dreams at The Santa Monica Museum Of Art for The L.A. Festival. In 1992, filename: FUTURFAX was commissioned by the Whitney Museum in New York. This work showed the audience a world of rationed food, government hydro-farms with the purpose of raising climate change dialogue and the possibility of human extinction.
In 1994 she premiered her 56-performer piece Zone at the UCLA Center for the Performing Arts Wadsworth Theatre. Between 1994 and 1997, with her newly formed Company, she revived the "Instant Theatre" of the 1950s and 1960s as TOHUBOHU! and went on to collaboratively create DBDBDB-d: An Evening (1994), TOHUBOHU! (1995–97), Meditation on the Life and Death of Ken Saro-Wiwa, Timepiece (1996), The Swans and The Unexpurgated Virgin (1997).
Rosenthal lectured at Carnegie-Mellon University's Robert Lepper Distinguished Lecture in Creative Inquiry series, as a lecturer/presenter at the first Performance, Culture and Pedagogy Conference at Penn. State (1996). Rosenthal was also a visiting Artist at The Art Institute of Chicago, New York University, University of California Los Angeles, UC Irvine, UC Santa Barbara, California Institute of the Arts, and at the Naropa, Esalen and Omega Institutes. Artist Robert Rauschenberg honored her in a suite of prints entitled Tribute 21.
Both Timepiece and The Unexpurgated Virgin premiered at the Fall Ahead Festival at Cal State Los Angeles. In 2000, at the FADO Performance Art Centre, Paul Couillard, in collaboration with the 7a*11d International Performance Art Festival, presented Rosenthal's final full-length performance piece, UR-BOOR, for two nights only. In 2000, aged 73, Rosenthal announced that she was retiring from performance to dedicate herself to her animal rights activism and pursue a career as a Painter.
Rosenthal died on May 10, 2015 in Los Angeles from congestive heart failure. She was 88.