Colleen M. O'Neil

Colleen has extensive experience in federal and state courts nationwide helping business clients resolve the following:

• Commercial contract disputes
• Shareholder and corporate disputes, including post-closing issues
• Estate and probate matters
• Trade secret claims
• Real property disputes
• Municipal and public law issues
• Title VII claims

Colleen has counseled and represented businesses, financial institutions and high-net-worth individuals in a variety of corporate, commercial, fiduciary and employment disputes with a results-oriented, practical approach.  

She has successfully prosecuted and defended a variety of business tort claims in both federal and state courts nationwide.

Colleen has represented municipalities and clients in the energy industry in various types of litigation, including contractual disputes, real estate disputes and employment matters.

Colleen has been recognized by Ohio Super Lawyers as a Top 50 Female Attorney in Ohio from 2013-2020, and as a Top 25 Female Attorney in Cleveland from 2013-2018 and in 2020. She has been selected for inclusion to the Ohio Super Lawyers list from 2012-2020. 

She joined Calfee in 1998, and she is a member of the firm’s Practice Planning and Growth Committee and the Diversity & Inclusion Committee. Colleen began serving as Vice Chair of the firm's Litigation practice group in 2019.

Honors & Recognitions

Ohio Super Lawyers, 2012-2020; selected for inclusion to the Top 50 Female Lawyers in Ohio list, 2013-2020; selected for inclusion to the Top 25 Female Lawyers in Cleveland list, 2013-2018 and 2020

Woman of Professional Excellence Award, YWCA of Greater Cleveland, 2010

Education

J.D., magna cum laude, Cleveland-Marshall College of Law, 1996

B.A., John Carroll University, 1992

Professional & Community

Cleveland-Marshall College of Law Board of Visitors, member

Irish American Law Society of Cleveland, founding member, former vice president

Magnificat High School, Chair, Board of Directors, May 2017 to present

Cleveland Marshall Law Alumni Association, board member

Leadership Cleveland Class of 2016

Cleveland Metropolitan Bar Association, member

Ohio Bar Association, member

American Bar Association and the ABA’s Litigation Section, member

Presentations

"Trade Secret Considerations to Avoid Business Risks," Calfee's 2019 Intellectual Property Seminar, June 27, 2019. 

"2018 Litigation Trends and Regulatory Changes," Calfee's 19th Annual Litigation Seminar and CLE presentation, with  Mitch Blair and David Bules, September 20, 2018.

"2017 Litigation Trends and Regulatory Changes," Calfee's 18th Annual Litigation Seminar and CLE presentation, September 13, 2017. 

“Mitigating Litigation Risk in Trust Administration,” National Trust Real Estate Association, May 3, 2017.

"Privacy and Data Security: 10 Steps for Minimizing Cyber Threats," Calfee's 16th Annual Litigation Seminar and CLE presentation, with Jamie Ramsey and K. James Sullivan, September 16, 2015

“Litigation Basics,” Ohio State Bar Association CLE Presentation

“U.S. Supreme Court Update with Emphasis on Class Action and Whistleblower/Retaliation Developments, including Dodd-Frank,” Calfee Complex Litigation Seminar, July 2011.

“Dealing With Difficult Depositions,” Ohio State Bar Association District 5 Annual Meeting, October 11, 2010.

“A.S.O.R.T. Training: Recent Operations and Lessons Learned,” Allied Special Operations Response Team, with Rick Goddard, February 2010.

“Law Enforcement and Civil Rights Litigation Training Seminar,” with Maura L. Hughes, February 2010.