KSS Architects Celebrates 25 Years of Shaping Philadelphia's Built Environment

PHILADELPHIA — September 23, 2026 — KSS Architects, a full-service architecture, interior design, and planning partnership, is celebrating the 25th anniversary of its Philadelphia office. Opened in 2001, the Philadelphia office has grown into one of KSS' most influential studios, becoming a proving ground for firm leadership and an anchor for an impressive portfolio across key sectors including K-12 and higher education, workplace, science and technology, and community development.

The milestone comes as KSS continues its broader evolution from a small, Princeton-based practice to a growing, multi-market firm with an established presence in Philadelphia and New York City. The Philadelphia market has proven both a catalyst and a model for the firm's growth, shaping how KSS builds relationships, develops talent, and expands into new sectors. The lessons learned in Philadelphia now serve as a template across the firm's Princeton and New York offices, informing how KSS grows in each market it serves. 

“From the beginning, our Philadelphia office has been about strengthening ties to the institutions and communities that make this city unique,” said Petar Mattioni, AIA, NCARB, LEED AP, Partner, KSS Architects. “Twenty-five years later, that same philosophy is central to everything we design, and we are proud of how the city has shaped us in return. It's a blueprint for the firm's future, matching design excellence to the institutions and communities we serve."

KSS opened its Philadelphia office in 2001, the firm's first major expansion since its founding in Princeton in 1983. Originally located in the Public Ledger Building on Independence Mall West, the office laid the foundation for KSS' long-standing relationships with local universities like the University of Pennsylvania, Temple University, Lafayette College, West Chester University, and Bryn Mawr College. Over the following two decades, KSS' early foothold became a platform for diversification, and the office continued its expansion into workplace, science and technology, civic, and community work. 

Today, the firm counts projects including the Pennovation Center at the University of Pennsylvania, WHYY's Hamilton Public Media Commons, KIPP Philadelphia Preparatory Academy, and the LEED Gold-certified AMY at James Martin Middle School among its defining Philadelphia work. The Pennovation Center transformed a former DuPont research facility into an entrepreneurial and innovation hub, earning LEED Gold certification and the 2017 AIA Philadelphia Design Merit Award. At WHYY, the firm turned a broadcast facility into a public-facing digital media laboratory, wrapping it in a translucent, LED-lit façade that showcases the station's work to the surrounding community. And the office's adaptive reuse of the historic John Greenleaf Whittier School into KIPP Philadelphia Preparatory Academy earned the 2024 Grand Jury Award from the Preservation Alliance for Greater Philadelphia. 

Most recently, KSS' work on Amy Gutmann Hall, Penn Engineering's new home for data science and AI, produced Philadelphia's first six-story mass-timber building, extending the Philadelphia office's longstanding relationship with the University of Pennsylvania into a new generation of research and teaching space. The firm has also partnered with the Elwyn School and the Mount Airy Community Development Corporation on innovative neurodiverse-learning initiatives, including a community-led master plan for literacy-focused learning environments. That plan now informs the firm's Live and Learn initiative on playful learning in affordable housing.

At the same time, the Philadelphia office has served as a pipeline for firm leadership, with many of its architects rising to senior roles across the firm. Mattioni, who joined KSS in 2001, now leads the firm's higher education practice and helps to shape the firm's overarching design philosophy. He has also been instrumental in building out the office's summer internship program as a crucial bridge to the next generation of designers. 

Last year, KSS promoted five people to Principal firm-wide, three based in the Philadelphia office. Alicia Heinsen, AIA, LEED AP BD+C, whowas promoted to Principal in October 2025, earned the title of Partner in May 2026, after nearly two decades with the firm. Heinsen, whose practice emphasizes human-centered experience, environmental responsibility, and community engagement, oversees more than 10 million square feet of commercial, industrial, and mission-critical work, which has helped to expand the profession's understanding of where meaningful architecture belongs. 

Other recent principal-level promotions in the firm's Philadelphia office include:

• Beth Emig, AIA, whose work centers on education and environments for neurodiverse learners, including projects at Rowan University's Discovery Hall and Bancroft's Mount Laurel campus
• Andrew Sniderman, AIA, a design leader on the Edelman Fossil Park & Museum at Rowan University who is helping guide the firm's thinking on the future of industrial markets
   

Mayva Donnon, AIA, NCARB, LEED AP, Partner, rounds out the office's senior leadership, with a design focus on learning environments, higher education, community clients, and neurodiversity, including work on Bancroft's Mount Laurel campus and Rutgers' Center for Adult Autism Services. As KSS expands its presence in New York City, several of these Philadelphia-based leaders are now also directing work in the firm's newer markets, extending the same model of institutional trust and long-term client relationships that built the Philadelphia office.

“The growth of the Philadelphia office reflects a deliberate investment in developing leaders here, and it is a large part of why this office has become a model for how the rest of the firm grows,” said Donnon. “As we begin our next 25 years in Philadelphia, KSS remains just as committed to the people and partnerships that have defined this office as we've been since Day One.”

About KSS Architects

KSS is an architecture, interior design, and planning partnership that aligns purpose with place to fully realize our clients' vision through the built environment. With offices in New York City, Princeton, and Philadelphia, KSS has a staff of more than 70 talented and dedicated design professionals passionate about creating built environments to stimulate learning, commerce, and community. We envision a world in which organizations align their purpose with the places they create; it is our mission to realize our clients' vision through the built environment. By designing today for tomorrow, KSS is bringing innovative projects to life through a thoughtful, human-centered, and sustainable approach. Learn more at kssarchitects.com.