William Michael O'Neill

William Michael O'Neill

Supreme Court of Ohio

Justice William M. O'Neill became the 156th justice to the Ohio Supreme Court on January 2, 2013. His life has been dedicated to public service. Justice O’Neill is a former judge, an army officer, a registered nurse, and an adoptive parent.

Prior to becoming a justice, Justice O’Neill served on the Eleventh District Court of Appeals from 1997 until 2007. He was most recently a registered nurse at Hillcrest Hospital, an affiliate of the Cleveland Clinic Foundation. He is also a former army officer, Vietnam veteran, and was both a newspaper and television reporter.

Justice O’Neill is a graduate of Ohio University, Cleveland Marshall College of Law, and Huron School of Nursing. Before being elected to the Eleventh District Court of Appeals, Justice O’Neill was an assistant attorney general for the state of Ohio from 1984 to 1996, representing the Ohio Civil Rights Commission and the Industrial Commission of Ohio. In private practice, he founded O’Neill & Brown in Geneva, Ohio, where he represented small businesses and individuals in both civil and criminal cases.

Justice O’Neill is a retired lieutenant colonel in the United States Army and was awarded the Bronze Star and the Army Commendation Medal for his service during the Vietnam War. He served as the commanding officer of the Armored Cavalry Troop from Painesville, and retired from the Ohio National Guard as a Judge Advocate General (JAG) Lieutenant Colonel in 1996. In 2007, LTC O’Neill, US Army (Retired), was inducted into the Ohio Veterans Hall of Fame.

Justice O’Neill has four grown children.

Jurisdictions Admitted to Practice
Placeholder image for jurisdictions.
Professional Experience
Supreme Court of Ohio
- Current
Registered Nurse
Hillcrest Hospital, an affiliate of the Cleveland Clinic Foundation
Eleventh District Court of Appeals
Assistant Attorney General
State of Ohio
Founding Partner
O’Neill & Brown
Ohio University
Ohio University Logo
Cleveland State University
Cleveland State University Logo
Huron School of Nursing
Placeholder image for education.
Hall of Fame
Ohio Veterans
LTC O’Neill, US Army (Retired)
Bronze Star and Army Commendation Medal
United States Army
For service during the Vietnam War.
Professional Associations
Ohio State Bar
Placeholder image for professional associations.
Speaking Engagements
Ohio Constitutional Modernization Commission
Websites & Blogs
Supreme Court of Ohio
Court biography
Contact & Map
The Supreme Court of Ohio
65 South Front Street
Columbus, MI 43215-3431
Telephone: (614) 387-9000