Catherine Castro Genthner was born in Bacolod, Negros Occidental province, Philippines. She was one of nine children of Benjamin C. Castro and Teresita Locsin Castro. The couple managed a cafeteria before emigrating to the United States. Catherine was educated at the Malate Catholic School in Manila and earned a Bachelor of Science in nutrition at St. Scholastica's College in Manila.

She came to the United States in 1974 as a guide at the Philippine Pavilion at the International Expo '74 in Spokane, WA. After the Expo closed, she moved to Boston to join her family where she worked at Beth Israel Hospital. She later moved to Baltimore where her father operated a small business. She worked as a dietitian at University Hospital and later as Chief Dietitian at St. Joseph Hospital in Towson.  While at St. Joseph, she enrolled in what is now the Carey Business School at Johns Hopkins University where she earned A Master of Administrative Science Degree.  It was there that she met her future husband, James Genthner, a former real property specialist for the Maryland State Highway Administration. The couple lived in Original Northwood when first married and later moved to Timonium in 2005. She worked briefly at Maryland General Hospital before working as a diabetes educator for Sanofi Aventis Pharmaceuticals. She worked briefly at GBMC before opening her private practice, Jacinta Nutrition and Diabetes Education Services as a diabetes educator in the Towson area.  She closed her practice and retired several years ago.

Catherine will always be remembered as an activist and a champion for the underdog. She loved kids and showed it by spoiling her nieces and nephews. She loved to volunteer and taught Catechism at The Church of the Nativity in Timonium, where she also acted as a Parking Minister.

Beloved by her family, Catherine leaves behind James, her husband of 35 years; siblings: Lorna & John McGinty of Baltimore, MD, Marijo & Tom Fadrigalan of East Taunton, MA, Charlie & Mary Castro of Framingham, MA, Cristina & Rob Palmisano of Baltimore, MD, Manny & Lisa Castro of Baltimore, MD, Ana & Brian Dempsey of Weymouth, MA, and Grace & Ruel Soriano of Clermont, FL; beloved aunts: Anita Locsin & Perla Castro; nephews: Arvin, Stephen, Peter James, Randy & Ryan; nieces: Ellen Mae, Maria, Marissa, Katrina & Gina and grandnephew/nieces: Matty, Paige, Maci & Mikaela. She is predeceased by parents Benjamin & Teresita Castro and brothers Melvin Castro and his surviving wife Arleen and Edwin Castro.

A visitation will be held at Peaceful Alternatives Funeral & Cremation Center, 2325 York Road, Timonium, on Thursday, April 18, 2024 from 7 PM to 9 PM. A Mass of Christian Burial will be held at The Church of the Nativity, 20 E. Ridgely Road, Timonium on Friday, April 19, 2024 at 1 PM. Interment to follow at Dulaney Valley Memorial Gardens. In lieu of flowers, contributions may be made in Catherine's name to The Franciscan Center, 101 W. 23rd St. Baltimore, MD, 21218, https://www.fcbmore.org/