Best Friends Animal Society Announces the Passing of Beloved Co-founder and Former CEO Gregory Castle

It is with profound sadness that Best Friends Animal Society announces the loss of co-founder and former CEO, Gregory Castle, who passed away suddenly on Saturday, May 17, 2025, from natural causes.  

Gregory, along with 26 co-founders, established Best Friends in 1984 when they broke ground for Best Friends Animal Sanctuary, now the country’s largest no-kill animal sanctuary and headquarters for the national animal welfare organization. As CEO from 2009 to 2018, he helped grow Best Friends into the leading national organization working to save dogs and cats in U.S. shelters and to make the entire country no-kill. 

Best Friends board president and co-founder Francis Battista said:   

“Gregory embodied the ethics of compassion and service. He devoted his entire adult life to helping animals and to making the world a better place. Losing Gregory is devastating, but his legacy of kindness and his commitment to the animals will live on through the work of Best Friends Animal Society.” 

Born in Cranbrook, England, in 1942, Gregory graduated from Cambridge University with a master’s in philosophy and psychology, and a passion for filmmaking. While at Cambridge he was a member of the venerable Cambridge Footlights, one of Britain’s oldest student sketch comedy troupes that produced some of the biggest names in British film and theater.  

He spent his childhood in Folkestone, England, a coastal access point during World War II that endured numerous bombings and air raids and served as a major landing spot for the Dunkirk evacuation. His father, Norman Castle, was a civil engineer for the British army who remained in Folkestone during the war while the rest of the town was evacuated. Gregory’s mother was among those who relocated to safety and Gregory was subsequently born in a country house in Cranbrook. His father was later awarded with one of Britain’s highest honors, an Order of the British Empire, for his heroic work in Folkestone during the war.  

Gregory spent the last 41 years in Utah, serving in a variety of roles at Best Friends. In the early days of the Sanctuary, Gregory installed the original water lines and electricity across 3,000 acres of high desert land, guided only by a set of DIY books. 

In 2000, along with his wife Julie, he started No More Homeless Pets in Utah, which evolved into No-Kill Utah (NKUT), a statewide coalition of animal welfare organizations, veterinarians and animal lovers collaborating to deliver low cost spay/neuter services, proactive shelter adoptions and public awareness campaigns to put Utah on the path to no-kill. The coalition became a model for cooperative efforts in the humane community throughout the country. 

Gregory played the bagpipes, flew airplanes and was an avid runner who completed 17 marathons over a 20-year period, including three Boston Marathons. At 73 years of age, he became the oldest person at the time to ever have completed the grueling seven-day Grand to Grand Ultra, which takes runners across 170 miles of Utah's back country.  

Gregory was 83 years old. He is survived by his wife Julie; his daughter Carragh Maloney; his granddaughter Zoe Glover, his brother Christopher Castle; sisters Jan Castle and Susan Duys, cats Ellie and Maggie, and dogs Sunny and Marley. His legacy will live on through a large and dedicated national community of animal lovers working to save the lives of homeless pets. He will be deeply missed.