Dr. William Dunnigan Cassidy III, of Princeton, West Virginia, died on September 28, 2026. Born in Bluefield, West Virginia, to William Dunnigan Cassidy Jr. and Josephine Williams Cassidy, Dr. Cassidy grew up in the coal-mining community of Gilliam, West Virginia. He earned his undergraduate degree from Hampden-Sydney College in Virginia, a master’s degree from The George Washington University, and a Ph.D. from Clayton University. Throughout his distinguished professional career, Dr. Cassidy held leadership roles in strategic planning and human resources administration with several major international corporations, including ITT, Penn Central Corporation, Warburg Financial, AKZO/Nobel, and Concurrent Computer Corporation. In 1982, he founded The Human Resource Partnership LLC, where he served as Chief Executive Partner. He also served as Vice Chair of West Virginia Ventures LLC. Dr. Cassidy was twice selected to serve as a member of the transition team for New Jersey Governor Chris Christie. Governor Christie later appointed him to the Board of Directors of University Hospital in Newark, New Jersey, where Dr. Cassidy served as Board Secretary and Chair of the Strategic Planning Committee. He also served as Vice Chairman of Broadway House in Newark, an inpatient HIV/AIDS care facility and hospice. His commitment to education and public service extended to numerous organizations. Dr. Cassidy served on the Board of the Smithsonian Science Education Center, a unit of the Smithsonian Institution, and was a Trustee Emeritus of Saddle River Day School in New Jersey. Dr. Cassidy also helped establish the Bergen County Drug Rehabilitation Center within the Bergen County Jail in New Jersey. He served as a trustee of the New River Unitarian Universalist Fellowship and was a member of the Union League Club of New York. An avid traveler with a lifelong curiosity about the world, Bill visited all 50 U.S. states, all seven continents, and more than 100 countries. Bill married Beverly Lisk Cassidy on November 25, 1967. They were married for more than 50 years and shared many adventures. In 2018, Bill reconnected with his high school sweetheart, Dr. April Vermillion Cassidy. He and April were married in January 2019. Bill was preceded in death by his parents, William and Josephine, and his beloved sister, Debra Ellen. Bill is survived by his three sons: William Dunnigan Cassidy IV of Georgia, his wife, Wendy, and his two sons Liam and Jake; Michael Cassidy of New Jersey, his wife, Kimberly, and their children Courtney and Conor; and Sean Cassidy of Georgia. Also keeping his memory alive and cherished are April’s son Kevin Beavers and his wife, Kerstin, of Düsseldorf, Germany. Services to celebrate Dr. William Cassidy’s life will be held at 11:00 A.M. Monday, October 12, 2026, at the Memorial Funeral Directory Chapel in Princeton, WV. Friends may visit with family on Monday, October 12, 2026 from 10:00 am until the service time. His cremains will be laid to rest at Roselawn Cemetery in West Virginia at a later date. While his life was marked by considerable professional achievement, public service, intellectual curiosity, and a deep commitment to the institutions and communities he served, his lasting legacy is his profound love for his family, who will miss listening to his stories, his bigger-than-life personality, and his generous heart. In lieu of flowers, donations may be made to Broadway House for Continuing Care at here.