Grant C. Killoran

Grant C. Killoran is a shareholder at O’Neil Cannon in Milwaukee, Wisconsin, and a past chair of the firm’s Litigation Practice Group. He represents clients in complex commercial and business litigation, health care disputes, and employment-related matters in Wisconsin state and federal courts and in courts around the country. His practice also includes contract and corporate disputes, restrictive covenant and trade secrets litigation, tort claims, appellate matters, alternative dispute resolution, risk management counseling, and arts and entertainment law.

Grant earned his law degree cum laude from the University of Minnesota School of Law, where he served as an editor and member of the Journal of Law and Inequality. He received his B.A. cum laude from Macalester College in St. Paul, Minnesota, and also studied at the East China School of Law and Politics in Shanghai. His academic background supports a practice that requires careful legal analysis, persuasive advocacy, and practical judgment across complex disputes.

Grant has substantial trial experience involving business, health care, and employment law conflicts. He assists clients with health care industry litigation and contracting, corporate and contract disputes, restrictive covenants, trade secrets, tort matters, appeals, and mediation or arbitration. He also advises businesses on risk management and legal strategy before disputes escalate. His courtroom experience across Wisconsin and other jurisdictions allows him to help clients assess legal exposure, develop litigation strategies, and pursue practical resolutions.

Grant C. Killoran is recognized in The Best Lawyers in America for Commercial Litigation and Litigation-Health Care and has been named among the Top 50 lawyers in Wisconsin and Top 25 lawyers in Milwaukee by Super Lawyers. He serves as the Wisconsin State Delegate to the American Bar Association and is a member of the ABA House of Delegates. He is also a Life Fellow of the American Bar Foundation, a Fellow of the Wisconsin Law Foundation, and a board member of Milwaukee Film.

Law Office Affiliations

• Shareholder, O’Neil, Cannon, Hollman, DeJong & Laing S.C.
• Member, American Bar Association, Wisconsin State Delegate
• Life Fellow, American Bar Foundation
• Fellow, Wisconsin Law Foundation
• Member, Milwaukee Bar Association, Milwaukee Justice Center Committee (2006–2009)
• Member, State Bar of Wisconsin, Multidisciplinary Practice Committee (1999–2000)
• Director, Milwaukee Young Lawyers Association (1992–2000)
• Barrister, American Inns of Court, Thomas E. Fairchild Inn (2000–2004)
• Member, American Health Lawyers Association

Licensed State

• Wisconsin

Education

• University of Minnesota School of Law
  Juris Doctor (JD) Cum Laude
• Macalester College in St. Paul
  Bachelor of Arts, Cum Laude

Awards & Badges