Ms. Brennan holds degrees in both nursing and law. She received her Bachelor's Degree in Nursing from the State University of New York at Binghamton in 1995, and her Juris Doctor degree from Brooklyn Law School in 2002.

After completing her undergraduate studies, Ms. Brennan was a staff nurse at Mount Sinai Medical Center and then worked in the Cardiothoracic Intensive Care Unit at New York Presbyterian Hospital. She continued to work at New York Presbyterian during law school, as well as holding a supervisory position in a local long-term care facility. Ms. Brennan continues to keep her license active.

Prior to becoming affiliated with the firm, Ms. Brennan was an associate at another civil litigation firm in New York City, specializing in medical malpractice. She is admitted to practice law in the state of New York and is a member of the New York State Bar Association.