After 72 remarkable years, Dénes Kassai departed peacefully at home, on March 5, 2026. Born on November 4, 1953, in Budapest to Hungarian parents (Dénes and Marta Kassai), he built a life defined by resilience, positivity, and unconditional love. He was devoted to his wife of 40 years (Kathryn Krippahne Kassai), to his 4 children (Denis Kassai, Gina Kassai Bland, Jeanette Kassai Brock, and Mike Kassai), and to his 3 grandchildren, (Sammy, Madeline, and Holly). He is also survived by his beloved sister, Marta Kassai.

Never a rule-follower, Dénes marched to the beat of his own drum. At the age of 17, Dénes and his family escaped by train from communist Hungary, and later they flew to California in 1972 to begin a new life. After winning second place in a national high-school math competition in Germany, his math prowess charted a course for his adult life, starting with college from Harvey Mudd, UC-Irvine, and UC-Berkeley. His aerospace-engineering career focused on fiber optics and space telescopes, with a top-secret clearance. His employers included Hughes, TRW, Northrup, and McDonnell Douglas, and he was an adjunct professor at Marymount College. Together with Kathryn, he co-founded Praxis Physical Therapy in 1988—a thriving PT clinic in San Pedro, CA.

Dénes had unbridled enthusiasm for every facet of his life. His long list of favorite things included: cooking, especially soups; sailing, which led to him meeting Kathryn in the British Virgin Islands; coaching soccer for his children’s teams; gerbera daisies; swimming in the Pacific Ocean; hiking Mt. Whitney; flying a propeller plane through the Grand Canyon with Kathryn; skiing; visiting Catalina Island; teaching math to his four kids; discussing philosophy with anyone who would listen; and traveling abroad—throughout Europe, the Caribbean, Mexico, and even to Antarctica.

Dénes would want to thank his beautiful family and all of his cherished friends for giving him such an abundance of love and joy throughout his entire life. The memories we share about him will forever be a part of our lives.

A Funeral Mass will be held at 10:30AM on Thursday, March 26, 2026 at Mary Star of the Sea Catholic Church in San Pedro, CA. A lunch reception celebrating his life will follow at noon at Michael’s Tuscany Room, in San Pedro, CA. All are welcome.