Ernestine Wiedenbach was born in 1900 in Hamburg, Germany, and her family moved to New York in 1909. She earned a Bachelor of Arts from Wellesley College in 1922 and her Registered Nurse's license from the John Hopkins School of Nursing in 1925. She got her Masters of Arts from Teachers College, Columbia University in 1934. In 1946, Wiedenbach earned a certificate in nurse-midwifery from the Maternity Center Association School for Nurse-Midwives in New York, and taught there until 1951. In 1952, she joined the faculty of Yale University as an instructor in maternity nursing. She became an assistant professor of obstetric nursing in 1954. When the Yale School of Nursing established a master's degree program, she became an associate professor and was the director of the major in maternal and newborn health nursing.