A retired family court judge in the State of New York, Judge Hamill began her career in nursing and worked as a registered psychiatric nurse in Louisiana and New York State until 1981. While living on the island of Bermuda, she volunteered at the Physical Abuse Center, where she became active, offering counseling and raising money to build that island's first domestic violence shelter for women and children. She earned a bachelor's degree from Excelsior College in 1986. Her long-range plan had always been to continue on to law school and advocate for family rights. After returning to New York State, she enrolled in the City University of New York School of Law at Queens College, choosing that school because of its commitment to "law in the service of human needs."

Upon graduation from CUNY School of Law in 1990, she practiced as an assistant district attorney in the Bronx County DA's office, primarily investigating and prosecuting sex crimes as well as cases of domestic violence and child abuse. She also served as law clerk to Bronx Supreme Court Justice Joseph Fisch. Judge Hamill was appointed to the family court bench in 2001. She now serves on the Board of Visitors for the CUNY School of Law, on the New York State Bar's Council on Children, and on the Board of the New York State Family Court Judges Association. She is also involved as a teacher and trainer for CUNY as well as other colleges and institutions. In 2004, she received Excelsior College's C. Wayne Williams Award, recognizing her community service.