John A. Onderdonk III

John Adrian Onderdonk, III, age 58, passed away on November 20, 2025 in Saratoga Springs, NY surrounded by loved ones. John passed after a brief, difficult battle with melanoma, leaving a hole in the hearts of his family, friends, and community.   

John was born February 15, 1967 in Philadelphia, PA to parents Mary-Ellen Stevens and John A. Onderdonk, Jr. A talented architect and artist, John graduated from Skidmore College, where he had a storied career on the crew team, and earned his Master of Architecture degree from Virginia Polytechnic Institute. In 2009 John was inducted into the Skidmore Athletic Hall of Fame. 

John was a beloved husband, father, brother, son, grandson, uncle, nephew, cousin, and friend. He was generous with his time and inspired those around him with his thoughtfulness, kindness, dry sense of humor, work ethic, and sense of adventure. John’s eye for detail made him a wonderful storyteller and historian. 

John worked as an architect for more than 30 years. He believed it was a privilege to design educational buildings that bring nature and technology together to create elegant, efficient, comfortable buildings that support great thinking and conserve resources. A Principal: AIA, NCARB, LEED AP at Mosaic Associates Architects, John shaped the firm’s practice and culture in profound ways and designed projects including the Gene Haas Center for Advanced Manufacturing Skills and the STEM Education Center at Hudson Valley CC. He took special pride in his work with the Saratoga Springs City School District and Skidmore College, where he designed the renovation and expansion of the Valentine Boathouse. 

John gave back to his community in many diverse and meaningful ways. He taught as an adjunct professor at RPI, attended career fairs to support aspiring architects, and oversaw the architectural internship program at Mosaic. John served on the Board of Directors of the Saratoga Arts Council and the Saratoga Springs Preservation Foundation. In 2009 he co-founded Spa:CX, a cyclocross race in Saratoga Springs, as a way to give back to the Saratoga/Capital Region bike community. More recently, he volunteered 2-3 times weekly at Bikeatoga, a community-based bike rescue nonprofit.  

John treasured being outdoors. He and his wife Natalie loved hiking in the ADKs together. A great cook, John took pride in commanding the kitchen during the holidays, scheming weeks ahead of Thanksgiving about the new dish he would make that year. Behind his serious exterior, John was silly. He loved bad SyFy movies (Sharknado), anything Godzilla, and watching Monty Python with his daughter Mia. 

John’s creativity and love for making things were infectious. Choosing the perfect pumpkin was a family affair every Halloween, and John’s jack-o'-lanterns were notable, from Grumpy Cat to Alien. He and his wife Natalie loved designing their daughter’s annual K-12 graduation posters, each of which would hang on her bedroom door until the next year’s poster was unveiled. After his daughter Mia joined her college ultimate frisbee team, John made sure everyone knew which team they were rooting for, crafting custom t-shirts for he and his wife and ringing a cowbell on the sideline to cheer for the team. They loved to travel together as a family; favorite vacations included canyoneering in Utah and exploring the Castle of the Moors in Sintra, Portugal.  

Spending time with his family was everything to John. He is survived by his wife Natalie Onderdonk, daughter Mia Pashoukos, sister Daphne Onderdonk (Ricardo Holdo), nephew Adrian Holdo, and several aunts, uncles, cousins, nieces, and nephews, as well as his beloved cats, Erastus, Minnie, and Roxy. He is preceded in death by both his parents.   

John had a saying, whether he was cleaning up a scraped knee or dealing with things when they got tough — “Rub some dirt on it.” He meant pick yourself up and keep moving forward. He always said it with love, often bringing laughter and levity to the situation. We were rubbing dirt all over his cancer right up to the end. John never gave up, and he never lost his sense of humor. We love you, John, always and forever.  

A gathering to honor and celebrate John will be announced on his memorial website, targeting early summer 2026. In lieu of flowers, the family requests that donations be made to Bikeatoga (https://www.bikeatoga.org/donate); Saratoga Springs Preservation Foundation (https://www.saratogapreservation.org/get-involved/donate-now/); or The Hyde Collection (https://www.hydecollection.org/donate/). 

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