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William J. O'Sullivan

Attorney Profile

Top Rated Business Litigation Attorney in Glastonbury, CT

O'Sullivan McCormack Jensen & Bliss PC
180 Glastonbury Blvd, Suite 210
Glastonbury, CT 06033
Phone: 860-258-1993
Fax: 860-258-1991
Selected to Super Lawyers: 2011 - 2022
Licensed in Connecticut Since: 1990
Practice Areas: Business Litigation, Alternative Dispute Resolution, Closely Held Business, Creditor Debtor Rights: Consumer, Creditor Debtor Rights: Business, Professional Liability: Defense, Professional Liability: Plaintiff, Real Estate: Consumer, Real Estate: Business
Attorney Profile

A highly regarded business litigation attorney, William J. O’Sullivan is a shareholder of O'Sullivan McCormack Jensen & Bliss PC. He practices out of the firm’s offices in Glastonbury, Connecticut, and he works with clients throughout Hartford County and other parts of the state. Mr. O’Sullivan received a Bachelor of Arts from the University of Connecticut in 1982, and he obtained his legal education at the University of Connecticut School of Law, graduating with his Juris Doctor in 1990.

Mr. O’Sullivan has worked on a variety of sophisticated matters during his tenure with the firm, and many of his cases have resulted in published opinions. He has represented both plaintiffs and defendants, and his workload has encompassed insurance fraud, foreclosures, noncompete agreements, fraudulent conveyances, eminent domain, trade secret misappropriation, employment law, shareholder and partner disputes, contract breaches and creditors’ rights.

Mr. O’Sullivan is frequently asked to deliver presentations to fellow professionals on topics related to his practice area, and he has had numerous articles published as well. He has authored an annual review of business litigation for the Connecticut Bar Journal every year since 2010, and he has also written extensively for other bar publications as well as for business journals. 

Mr. O’Sullivan has received a great deal of favorable recognition from his fellow members of the bar for the high quality of his work as well as for his successful track record both in the courtroom and at the negotiating table. Among his many honors are an AV Preeminent* peer review rating through Martindale-Hubbell and being selected for inclusion in The Best Lawyers in America. Admitted to practice in Connecticut, he is also admitted to practice before the U.S. District Court for the District of Connecticut, the U.S. District Court for the Southern District of New York, the U.S. Court of Appeals for the 2nd Circuit and the Supreme Court of the United States. 

*AV®, AV Preeminent®, Martindale-Hubbell Distinguished and Martindale-Hubbell Notable are certification marks used under license in accordance with the Martindale-Hubbell certification procedures, standards and policies. Martindale-Hubbell® is the facilitator of a peer review rating process. Ratings reflect the anonymous opinions of members of the bar and the judiciary. Martindale-Hubbell® Peer Review Rating™ fall into two categories – legal ability and general ethical standards.

Practice Areas
  • 20%Business Litigation
  • 10%Alternative Dispute Resolution
  • 10%Closely Held Business
  • 10%Creditor Debtor Rights: Consumer
  • 10%Creditor Debtor Rights: Business
  • 10%Professional Liability: Defense
  • 30%Other
Focus Areas

Trade Secret, Non-Compete Agreements, Arbitration, Mediation, Collections, Foreclosure, Landlord/Tenant


12 Years Super Lawyers
  • Super Lawyers: 2011 - 2022

About William J. O'Sullivan

First Admitted: 1990, Connecticut

Professional Webpage:


  • State v. Knybel, 281 Conn. 707 (2007) (criminal law; constitutional law)
  • Pettola v. Nissan Motor Acceptance Corp., 44 F.Supp.2d 442 (D.Conn. 1999) (Consumer Leasing Act)
  • Ryan v. Sullivan, Hill, Lewin, Rez, Engel and Labazzo, 316 B.R. 101 (D.Conn. 2004) (fraudulent transfer; preference)
  • PPG Industries v. Webster Auto Parts, Inc., 128 F.3d 103 (2d Cir. 1997) (wrongful termination of distributorship; implied waiver of arbitration)
  • Putnam Park Associates v. Fahnestock & Co., 73 Conn.App. 1 (2002) (commercial lease)
  • Kazlon Communications, LLC v. American Golfer, Inc., 82 Conn.App. 593 (2004) (contract; release; offer-of-judgment statute)
  • LMK Enterprises, Inc. v. Sun Oil Co., 86 Conn.App. 302 (2004) (contract; eminent domain; franchise law)
  • Davis v. Hebert, 105 Conn. App. 736 (2008) (restoration of withdrawn case to docket; mutual mistake)
  • Somers v. Chan, 110 Conn. App. 511 (2008) (suit by assignee of judgment; res judicata; supervisory power of court)
  • Mitchell v. Redvers, 130 Conn.App. 100 (2011) (constructive trust; Connecticut Marketable Record Title Act)
  • Mierzejewski v. Brownell, 152 Conn.App. 69, 97 A.3d 61 (2014) (easement; res judicata)
  • Bhinder v. Sun Co., Inc., 246 Conn. 223 (1998) (tort reform; apportionment of liability)
  • Bhinder v. Sun Co., Inc., 263 Conn. 358 (2003) (constitutional law; retroactive effect of legislation)
  • Robinson v. Coughlin, 266 Conn. 1 (2003) (Uniform Fraudulent Transfer Act)

Scholarly Lectures/Writings

  • Connecticut Bar Journal, "Business Litigation: 2019 in Review," Vol 93, No. 1
  • “Beware of Treacherous Pitfalls When Selling Your Business – Remember, Cash is King,” Hartford Business Journal, April 5, 1999
  • “Under Connecticut Law, You May Own a Franchise – And Not Realize It,” Hartford Business Journal, July 19, 1999
  • “Avoiding Lawsuits by Your Ex-Employer,” Hartford Business Journal, September 20, 1999
  • “A Forgotten Asset in Selling a Business: The Valuable Star Employee,” Hartford Business Journal, October 4, 1999
  • “Stop the Tape: Recording Phone Calls Can Backfire Disastrously,” Hartford Business Journal, November 15, 1999
  • “No, You Can’t Get Legal Fees – and No, You Can’t Get Interest,” Hartford Business Journal, January 10, 2000
  • “Beware: When Co-Signing or Guaranteeing a Loan, It’s Easy to Get In, but a Lot Harder to Get Out,” Hartford Business Journal, June 19, 2000
  • “Warning to Ex-Employees: Copy, Delete, Get Sued,” Hartford Business Journal, August 7, 2000
  • “Read Before You Sign,” Hartford Business Journal, March 25, 2002
  • “Buying a Business – Is it a Legitimate Deal or a Scam?”, Hartford Business Journal, September 30, 2002
  • “How to Discourage Your Employees From Stealing Your Company,” Hartford Business Journal, February 17, 2003
  • “Attorney and Counselor – Make Sure Your Lawyer is Both,” Hartford Business Journal, April 14, 2003
  • “Pre-Printed Legal Forms Might Cost You a Little Now and a Lot Later,” Hartford Business Journal, October 16, 2003
  • “Starting a Partnership: Should You Share a Lawyer, Or Hire Your Own?”, Hartford Business Journal, January 19, 2004
  • “In Recession, Watch for the Bleed,” Hartford Business Journal, May 18, 2009
  • “Litigating and Lobbying: To Win, You Might Need Both,” Connecticut Law Tribune, September 8, 2003
  • “Litigating Cases on a Budget: Risky and Getting Riskier,” Connecticut Law Tribune, June 30, 2005
  • “High Court Nominee Pitched In To End Strike,” Connecticut Law Tribune, June 8, 2009
  • “Decision Highlights Risk for Divorce Lawyers,” Connecticut Law Tribune, June 4, 2012
  • “Implied Strict Foreclosure Under Article 9 of the Connecticut UCC,” Connecticut Lawyer, February 1998
  • “Consideration for Covenants Not to Compete: Is It Enough to Say, ‘You’re Not Fired?’”, Connecticut Lawyer, February 1999
  • Cited in C. Tait and E. Prescott, Connecticut Evidence (4th Ed. 2008), section 3.5.2, p. 118, Connecticut Lawyer
  • “Proving Fraud: The History and Future of Connecticut’s ‘Clear and Convincing Evidence’ Rule,” Connecticut Lawyer, April 2004
  • “Threatening Criminal Prosecution in a Business Tort Case,” Connecticut Lawyer, November 2004
  • “Getting Leverage in a Business Tort Case: Hard Bargaining or Blackmail?”, Connecticut Lawyer, August/September 2006
  • “Baseball Law 101,” Connecticut Lawyer, April 2007
  • “Pleading (and Waiving) the Fifth in a Business Tort Case,” Connecticut Lawyer, March 2009
  • “Drafting an LLC Operating Agreement: A Litigator’s Perspective,” Connecticut Lawyer, October/November 2012
  • Connecticut Bar Journal, “Business Litigation: 2010 in Review,” Vol. 85, No. 2
  • Connecticut Bar Journal, “Business Litigation: 2011 in Review,” Vol. 86, No. 2
  • Connecticut Bar Journal, “Business Litigation: 2012 in Review,” Vol. 87, No. 2
  • Connecticut Bar Journal, “Business Litigation: 2013 in Review,” Vol. 87, No. 4
  • Connecticut Bar Journal, “Business Litigation: 2014 in Review,” Vol. 88, No. 4
  • Connecticut Bar Journal, "Business Litigation: 2015 in Review," Vol. 90, No. 2
  • Connecticut Bar Journal, "Business Litigation: 2016 in Review," Vol. 90, No. 3
  • Connecticut Bar Journal, "Business Litigation: 2017 in Review," Vol 91, No. 3
  • Connecticut Bar Journal, "Business Litigation: 2018 in Review," Vol 92, No. 3

Pro bono/Community Service

  • Past Deputy Mayor and Councilman, Rocky Hill, Connecticut, Town Council
  • Tenor, St. James Roman Catholic Church Choir
  • Past Member, Rocky Hill Economic Development Commission
  • Past Member, Rocky Hill Planning and Zoning Commission


  • Selected for inclusion in Best Lawyers in America, Commercial Litigation, 2021
  • Named a New England “Super Lawyer,” Business Litigation, 2011-present
  • Recipient of the Martindale-Hubbell AV Peer Review Rating

Bar/Professional Activity

  • Connecticut
  • Statewide Grievance Committee, 2009-2018
  • Hartford County Bar Association
  • Connecticut Bar Association, Chair, Litigation Section, 2017-2019
  • United States District Court, Southern District of New York
  • United States District Court, District of Connecticut
  • United States Court of Appeals, Second Circuit
  • United States Supreme Court

Educational Background

  • University of Connecticut, B.A., 1982


  • “Bill O'Sullivan is a hard-nosed, skilled business litigator.”

These comments were made by fellow attorneys during the annual nomination process.

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Office Location for William J. O'Sullivan

180 Glastonbury Blvd
Suite 210
Glastonbury, CT 06033

Phone: 860-258-1993

Fax: 860-258-1991

Last Updated: 6/24/2022

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