In 1940, Amsterdam was elected to the New York City Municipal Court, becoming the first woman to serve as a judge of that court. She was reelected to that position in 1949. In 1954, Amsterdam was appointed to fill a vacancy as a justice of the City Court, a higher-ranking tribunal on which she was again the first woman to serve as a judge; she was elected to a full term on that court in 1955. In 1958, Amsterdam was elected as a justice of the New York State Supreme Court, the state's highest trial court. She served in that position until her retirement in 1975.
Birdie was also an activist and leader in her community. She led a war bond drive in the Lower East side in addition to being involved as a district co-leader in the Manhattan Democratic Club.[4]
Personal life
Briefly married and later divorced to Dr. Robert Dunn. Spent many years living with Ruth and Judge Milton Sanders.[4]