Marie Pichel Warner was born in Cincinnati, Ohio, one of five children of Isaac and Lily Pichel. She earned a B.S. degree from the University of Cincinnati, then was a medical social worker. In 1922, she married Louis J. Levinson, and the following year graduated from the University of Cincinnati College of Medicine. She was assistant medical examiner for the University of Cincinnati’s Department of Hygiene in 1923-1924. Following her husband’s untimely death, she moved east and remarried in 1933 to Dr. Benjamin W. Warner.
She opened a private practice in New York City specializing in obstetrics and gynecology, and much of her career from this point focused on family planning. She served as assistant medical director of Margaret Sanger's Clinical Research Bureau and as director of the Family Planning Clinic in Harlem. She also founded the maternal health clinic at the Recreation Rooms Settlement House in Manhattan and became its medical director in 1940. She served as medical director of contraceptive clinics at Jewish Memorial Hospital. Dr. Warner lectured on the topic of family planning at New York University, gave talks on the radio, produced a film on the subject in the 1930s, and traveled around the USA to give lectures and visit clinics. In addition to these activities, she published numerous articles and several books on contraception and infertility. She also held various assistant or adjunct hospital appointments at Mount Sinai Hospital and Jewish Memorial Hospital, and was visiting obstetrician at the New York Infirmary of Beth Israel Medical Center. She retired only a few months before her death at age 84.