Hugh Michael O’Brien IV

Hugh Michael O’Brien IV — “Mike” — 57, of San Diego, California, passed away on 3 August 2026 at UC San Diego Jacobs Medical Center, surrounded by his family, after a three-and-a-half-year fight with stage 4 pancreatic cancer.

He was born on 31 July 1969 in Subic Bay, Philippines, to Hugh Michael O’Brien III and Julie Apelo O’Brien. After graduating from George Dewey High School he attended San Diego State University, where he received a Bachelor of Science in Computer Science. He spent thirty years as a software engineer, most of them with defense contractors, including more than twenty years at L3Harris.

He met Maribelle in college in 1989. They married in 1993 and received the sacrament of holy matrimony in the Catholic Church in 1998. They built their family and their home in San Diego and worshipped at St. Anne Catholic Church, where Mike loved the Traditional Latin Mass.

He was a devoted husband, father, and brother. He loved figuring out how things worked and making them better, and he loved the outdoors, camping, and the open road. A man of deep faith, he met his illness with grace, humor, and courage.