A Life of Service: The Story of EODCM Sean O’Day

From the quiet hills of Branson, Missouri, to the far reaches of combat zones across the globe, Master Chief Sean O’Day’s journey is one defined by dedication, courage, and a steadfast commitment to service.

Sean O’Day began his naval career in August 1992, when he enlisted in the United States Navy and reported to Recruit Training Command, Great Lakes. Following graduation, he attended Gunner’s Mate “A” School, launching a career that would soon span over three decades. His first sea duty took him across the Atlantic to Gaeta, Italy, where he served aboard the USS Belknap (CG-26). He went on to serve aboard the USS LaSalle (AGF-3) and the USS Denver (LPD-9) before transferring to the Active Naval Reserve in 1998.

Seeking new challenges within the Reserves, O’Day earned qualification as a Reserve Explosive Ordnance Disposal (EOD) Apprentice with EOD Mobile Unit SEVEN. Two years later, driven by purpose and passion, he returned to active duty and reported to EOD Mobile Unit THREE, where he served as both a Marine Mammal Handler and Leading Petty Officer for the MK5 Sea Lion Deep Recovery System. In 2002, he graduated from the prestigious Navy Explosive Ordnance Disposal School in Eglin, Florida, marking the beginning of an extraordinary 22-year career in one of the Navy’s most elite communities.

Throughout his service, Master Chief O’Day completed four deployments to the U.S. Central Command Area of Operations in support of Operations Enduring Freedom, Iraqi Freedom, and New Dawn—three of which placed him in direct combat. His technical expertise and leadership supported units including Naval Special Warfare Squadron THREE, Task Force Troy, Task Force 56, and the 75th Ranger Regiment.

Beyond the battlefield, O’Day continued to shape the EOD force through key leadership assignments. He served as the Nuclear Division Leading Chief Petty Officer (LCPO) at EOD Training and Evaluation Unit ONE and as the Readiness and Training LCPO at EOD Mobile Unit ELEVEN. His exceptional leadership led to his selection for the Command Master Chief (CMC) Program in January 2017, a testament to his character and influence.

As a Command Master Chief, O’Day guided Sailors and operations at EOD Training and Evaluation Unit TWO and EOD Mobile Unit TWO, later serving as the CMC and Senior Enlisted Advisor of EOD Group TWO—one of only two major EOD commands in the U.S. Navy. His impact extended fleetwide as he assumed the role of Chairman of the EOD Senior Enlisted Advisor Group, representing the entire enlisted EOD community and providing policy guidance to senior Navy leadership.

Yet, beyond the uniform, Sean O’Day’s life is also defined by personal strength and resilience. For the past 18 years, he has been a devoted father to a special needs daughter, facing challenges at home with the same steadfast resolve that carried him through combat.

Now, as Master Chief O’Day approaches the culmination of his remarkable Navy career, his legacy is one of service, sacrifice, and mentorship. His story is not only that of a Sailor and leader but also of a man who has lived every day guided by honor, family, and the values of the Chiefs Mess—a passion that continues to inspire those who follow in his wake.