Hayley MacMillen

Biography

Hayley MacMillen brings to GMSR experience representing clients in all stages of civil and administrative litigation, including at trial.  Her litigation expertise informs her detail-oriented approach to the appeals process.

Before joining GMSR, Hayley clerked for Judge Gabriel Sanchez of the United States Court of Appeals for the Ninth Circuit.  This role lent her firsthand knowledge of how rigorous command of the facts and law can help persuade judges and secure appellate victories.  Having worked as a litigator at a large firm following her clerkship, Hayley understands the entire life cycle of a lawsuit, preparing her to work with trial counsel and clients to identify opportunities for success on appeal.

Hayley is an inaugural member of the Bay Area Appellate American Inn of Court, founded in 2025.  Her community service includes serving as a volunteer mentor for Law Academy, a program of the San Francisco Unified School District and the Bar Association of San Francisco’s Justice and Diversity Center that teaches high school students legal concepts and professional skills.

Hayley graduated from the University of California, Berkeley, School of Law, where she was elected to the Order of the Coif and received the Thelton E. Henderson Center Public Interest and Social Justice Certificate.  Before law school, Hayley worked as a journalist specializing in reproductive health and rights.