Dr. Mark Stephen O’Brien, a devoted husband, father, grandfather, physician and teacher, passed away peacefully on June 13th, 2025, at the age of 71.
Born January 1, 1954, in Ottumwa, IA. Mark was blessed with a sense of purpose and compassion. On April 26th, 1974, Mark married his best friend and love of his life, Murline Guffey. Together they built a life where love, faith and family forged bonds beyond breaking. He was a proud father to Matthew David, Michelle Renee, and Melody Faith. Later welcoming Reese O’Brien, wife of Matthew and Cyril Tamakloe husband of Melody into the family with loving arms.
Mark began pursuing his lifelong passion of medicine in 1977 when he entered medical school at the Kirksville College of Osteopathic Medicine in Kirksville, MO, where he laid the foundation for a life of unwavering service to others. In 1982, Mark and family moved to Unionville, MO, establishing a family practice. He was enthusiastic and fierce in his patient advocacy and care. In 1998 he shifted his medical focus from family practice to Emergency Medicine, thriving in the ever-changing environment. His dedication and leadership helped shape Emergency Departments across the region. From his birthplace, Ottumwa, to Moberly to Maryville and a dozen hospitals in between, patients gazed into his blue eyes and saw an unwavering commitment to care.
Another of Mark’s deepest joys were his grandchildren – Garrett, Jadyn, Gavin, Seth, Karis, Leah and Adric. He cherished every moment with them, teaching lessons of humility, wisdom, medicine and woods-lore. Hunting with the grandkids or riding around the farm were hours he would always trade anything for. Mark encouraged everyone around him to think deeply, and always seek knowledge.
He is preceded in death by his daughter Michelle Renee and his brothers, Lance and James. Mark held their memories close to him always, drawing strength from their love.
A visitation will be held on Thursday, June 19th at 1:00 p.m. A Funeral service will follow at 2:00 p.m. at the Unionville First Christian Church.
Burial will follow at the Unionville Cemetery.
Dr. Mark O’Brien leaves behind a legacy of compassion, integrity and love. He touched countless lives, giving aid and compassion freely. He will be remembered not only as an exceptional physician and friend but also for the gentle, wise and generous soul he shared with the world.
A life lived with purpose, a man dearly loved – he will be missed beyond measure.
In lieu of flowers contributions in his memory can be given to the Unionville Cemtery.
Casady-Luscan Funeral Solutions is honored to care for and minister to the O’Brien family during this time.
