Marissa De Siena P ’32, ’36, Head of the Upper School, 2023-present, started her days in independent schools as a teacher, though that was never her plan. In fact, growing up with two parents in the profession, she vowed she would do anything but follow in their footsteps. And yet, education—shaped by curiosity, circumstance, and an enduring sense of purpose—found her anyway.
Marissa began her professional journey as a doctoral student at UCLA, where she pursued Russian and Eastern European Studies with the intention of entering higher education. After multiple research trips to Russia, she discovered that while her original prospectus focused on educational movements, her true intellectual passion was diplomatic history. Just as her academic interests were crystallizing, budget cuts threatened her program and the internship she needed to complete her degree. Faced with uncertainty, Marissa made a pivotal decision: she stepped away from UCLA and accepted a position teaching history at an independent high school in Santa Monica.
What began as a detour quickly became a calling. She spent eight years at the school, where strong relationships, institutional challenges, and moments of mismanagement opened the door for her to assume increasing leadership responsibilities. Without planning it, Marissa found herself growing into administration, discovering both an aptitude and a passion for shaping school culture and supporting teachers and students.
Her next chapter took her to the Westmark School in greater Los Angeles, a school dedicated to students with learning differences. There, Marissa deepened her understanding of how the brain works and how students learn in diverse and individualized ways. She served in multiple roles—Academic Counselor, Division Head, Curriculum Coordinator—and gained experience in mission-driven education that centered students’ strengths and needs. During this time, she also participated in the National Association of Independent Schools (NAIS) yearlong Aspiring Heads Fellowship. Through that experience, she realized she wanted to take everything she had learned in a specialized setting and apply it more broadly and benefit all types of learners in a less specialized school environment. That realization quietly set the stage for Harley.
Though originally from the Rochester area, Marissa had never imagined returning. In 2020, just before the pandemic shutdown, she attended an NAIS conference in Philadelphia and noticed Harley School listed as a presenting school. Curious, she attended the session and introduced herself to Lars Kuelling P ’18, ’20 (Assistant Head of School for Academic Programs, 2016-20, Interim Head of Middle School, 2020-22). Two years later, on her first visit back to Rochester in a long time, she reached out to Larry Frye P ’12, ’15, ’15 (Head of Upper School, 2004-18, Head of School, 2018-23) and toured Harley’s campus. The experience left a deep impression, from the Nature Center and Winslow Natural Playground & Outdoor Learning Center to the Harley Hospice program, that she brought these ideas back to her school out in California.
There was also a personal connection she hadn’t anticipated. Marissa’s mother had worked with Marilyn Fenster (Lower School, 1975-80, 1989-2021), helping place University of Rochester student teachers at Harley. Marissa’s mother visited Harley and said to her, “You have to work there!” Marissa laughed it off—she had been clear with her parents that she was never moving back to Rochester and told her, “Don’t hold your breath.” Soon thereafter, she saw the posting for Head of the Upper School on the NAIS website.
She applied without expectation, but with a surprising sense of calm. From the very beginning, she felt deeply connected to the people and aligned with the school’s mission. She noticed the wide-ranging interests and talents of the faculty, the respect they showed one another, and their shared commitment to student learning. After her interview, teachers reached out to her to express that they felt the connection, too. For Marissa, it was a rare and powerful moment of mutual recognition. Everything seemed to fall into place—right people, right time, right school.
As Head of the Upper School, Marissa is most proud of the ways the division has grown intentionally and collaboratively. She has worked to expand course offerings that reflect both student interests and faculty passions, including a strengthened Health and Wellness program developed in partnership with Theron Tate (Physical Education and Health Educator, 2024-present). She helped establish an Upper School Day of Service, engaging students in hands-on volunteering at Harley and local nonprofits, with the goal of making service a lasting habit rather than a one-time event.
She also led the launch of the Upper School’s first experiential Grade 12 trip to Atlanta, an immersive learning experience designed to help students better understand the world around them. Through visits to historic sites, cultural institutions, and community spaces, students engaged deeply with history and the civil rights movement.
Equally important to Marissa is the culture among the faculty. She has worked to foster cohesion, celebration, and trust within the division, emphasizing transparency, communication, and respect for the many roles teachers play. She feels privileged to work alongside such intelligent, dedicated educators and to advocate for what they believe in. She believes their energy is what ultimately fuels student growth.
Under her leadership, the Upper School has developed clearer expectations, firmer guidelines, and greater consistency—creating transferable institutional norms while remaining true to Harley’s mission. Marissa sees her role as both steward and advocate: ensuring that structures are strong, values are lived, and the division continues to evolve without losing its core identity.
What brings her the most joy are the everyday moments. Spirited debates in the faculty room that reveal just how deeply teachers care. Watching students take pride in their work, knowing she helped create the conditions for that success. Seeing students step into leadership roles at Morning Meeting. Celebrating student performances and sporting events, both at Harley and off-campus.
Looking ahead, Marissa is excited about expanding internship opportunities so students can apply their learning in real-world contexts. She is eager to deepen cross-curricular work, particularly through Harley’s Commons, highlighting what makes it such a distinctive and powerful space for learning, connection, and collaboration.
