Mark is a litigator companies want on their side when the stakes are high. With over 40 years experience trying cases and settling business disputes, his clients see him as fair-minded but aggressive in bet-the-company cases — always prepared to go to trial, but with an ability to quickly discern the best course of action for their business. His first step with any new matter is to sit down with his client and get a thorough understanding of their needs and tolerances. Only then can they develop a proper legal strategy — whether tackling complex corporate/shareholder disputes or high-profile client disputes or a white collar defense. Because business disputes often take unexpected twists and turns, Mark’s style is to err on the side of more communication, making an effort to explain situations and legal options in clear, concise business terms.

His legal experience is comprehensive, including business and fiduciary litigation, white collar crime and investigations, representing municipalities as well as appealing and advocating for business and individuals at the state and federal levels. His clients have included Procter & Gamble, the Archdiocese of Cincinnati and a variety of large privately-held and public companies, and individuals and institutions serving in fiduciary capabilities.

He pays close attention to the development of the firm’s next generation of litigators. He believes that Dinsmore attorneys need to be “hands-on” early in their careers — gaining trial and appellate experience whenever possible — increasing the firm’s ability to provide a deep and experienced bench well into the future.

Mark teaches legal ethics as an adjunct professor of law at the University of Cincinnati College of Law.  He is also a champion for the less fortunate, having served as trustee and former president of the Legal Aid Society of Greater Cincinnati, the Volunteer Lawyers for the Poor, and the Ohio Justice & Policy Center.  He has also served as board chair and continues to serve on the board of the Center for Closing the Health Gap.

Bar Admissions

Ohio

U.S. Supreme Court

U.S. Tax Court

U.S. Court of Appeals for the Sixth Circuit

U.S. District Court for the Southern District of Ohio

U.S. District Court for the Northern District of Ohio

U.S. District Court for the District of Colorado

Education

• University of Michigan Law School (J.D., 1972)
• Hope College (A.B., cum laude, 1970)

• Peer Review Rated AV in Martindale-Hubbell
• Best Lawyers^® 
  • "Lawyer of the Year" in Cincinnati for Appellate Practice (2012, 2014, 2019, 2021) 
  • "Lawyer of the Year" in Cincinnati for Litigation  (2009, 2013)
  • "Lawyer of the Year" in Cincinnati for Litigation – Municipal (2015)
  • Appellate Practice; Arbitration; Bet-the-Company Litigation; Commercial Litigation; Litigation – Municipal; Mediation (2021)
• Ohio Super Lawyers^®
  • For Business Litigation (2021)
• Who's Who in America 
• Who's Who in the Midwest
• Who's Who in Law
• Chambers USA^®: America's Leading Lawyers for Business, Litigation: General Commercial 
• Cincy Leading Lawyer by Cincy Magazine
• American Board of Trial Advocates
• Benchmark Litigation Star in Ohio (2016)

• Ohio Ethics Commission
• University of Cincinnati College of Law, Legal Ethics adjunct professor 
• Cincinnati Bar Association, Ethics Committee past chair
• Ohio State Bar Association, Litigation Section
• American Bar Association, Litigation Section 
• State of Ohio, past deputy special prosecutor
• City of Blue Ash, Ohio, city solicitor
• National Diocesan Attorneys Association
• Cincinnati Southern Railway, trustee and president (1992 - 2012) 
• Potter Stewart Inn of Court, master of the bench
• Supreme Court of Ohio, Rules Revision Committee past member
• Indian Hill Church, Board of Stewards past president
• University of Cincinnati College of Law, Board of Visitors
• The Health Gap, Board of Directors chair