Education & Honors

University of Michigan Law School, 2000, J.D., summa cum laude

Articles Editor, Michigan Law Review

Darrow Scholar & Bates Memorial Award

Internship for Bruno Simma of the United Nations International Law Commission

University of Texas, 1994, B.A., with Highest Honors, Biology and Plan II Honors Liberal Arts

Government service

Deputy Chief Counsel, National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling, 2010-2011

Law Clerk, Honorable Sandra Day O'Connor, United States Supreme Court, 2003-2004

Assistant Federal Public Defender, Washington, D.C., 2001-2003

Law Clerk, Honorable Harry T. Edwards, Chief Judge, United States Court of Appeals for the District of Columbia Circuit, 2000-2001

Awards & Recognition

Named to Best Lawyers in America, 2015

Bar admissions



Professional activities and community service

Board of Directors, Colorado Lawyers Committee

Sean C. Grimsley

Denver Office
1899 Wynkoop Street
Suite 800
Denver, CO 80202
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Professional Practice

Sean Grimsley serves as trial counsel and legal advisor in high-profile litigation matters, both in the U.S. and abroad. Sean has a diverse practice, including antitrust, oil and gas, class actions, accounting malpractice, and intellectual property matters. Most recently, he first-chaired a $50-million damages trial for client Tyco where he and his team stepped in months before trial and obtained a jury verdict for roughly 10% of plaintiffs’ demand, which a previous jury had awarded in full. In the last four years, Sean and his colleagues have tried a multi-billion dollar antitrust jury case in Texas state court (which settled favorably during trial), won a major class action appeal in the Seventh Circuit, and tried a patent case and separate post-verdict damages proceeding in the Eastern District of Texas. Sean has also served as lead counsel and advisor for a major U.S. oil company in both China and the U.S. regarding a highly-publicized oil spill in Chinese territorial waters. 

Sean recently served as Deputy Chief Counsel to the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling in Washington D.C. Sean and Fred Bartlit investigated and presented findings to the President's Commission regarding the root causes of the worst oil spill in the nation's history. You can see Sean at the two-day hearing where the investigative team presented their findings here: The Chief Counsel's report is available here: The Co-Chairs of the Commission, Senator Bob Graham and Bill Reilly, describe the investigative team’s work here:

Sean has tried eleven cases, argued three appeals, and advised on and prepared to try many others. Sean’s breadth of experience representing both defendants and plaintiffs ensures that early case assessment, discovery, motions practice, and expert work focus on the facts and arguments that actually matter to achieving the best possible result at trial or through settlement.

Prior to joining the firm in 2004, Sean served as law clerk to Justice Sandra Day O’Connor of the U.S. Supreme Court and Chief Judge Harry T. Edwards of the U.S. Court of Appeals for the D.C. Circuit. Sean also worked for two years as an Assistant Federal Public Defender in Washington, D.C. serving as trial and appellate counsel for indigent criminal defendants in federal court. Sean graduated summa cum laude from Michigan Law School in 2000. He obtained a B.A. in Plan II Honors and Biology with Highest Honors from the University of Texas in 1994. He lives in Denver with his wife Emily and their three wonderful (most of the time) children.

Cases tried or otherwise taken to judgment

General Commercial Litigation

Core-Mark v. Sonitrol (Adams Cty, Colo. 2014)
First-chair trial counsel for defendant Sonitrol, former subsidiary of Tyco, International, in one-week damages-only trial where plaintiffs were seeking over $50 million in damages because Sonitrol willfully and wantonly breached its burglar-alarm monitoring contract by failing to detect three burglars in plaintiffs’ warehouse who looted the warehouse and eventually lit fires that ultimately destroyed the warehouse. The jury awarded plaintiffs the damages number sponsored by Sonitrol, which was roughly 10% of what plaintiffs were seeking.


American Airlines v. Sabre, et al. (Tarrant Cty, Tex., N.D. Tex. 2011-2012)
Trial counsel for Sabre in antitrust suit brought by American Airlines in both state and federal courts in Texas alleging unlawful monopolization, conspiracy and illegal contractual arrangements and seeking nearly $3 billion in damages. Case proceeded to trial in state court in Ft. Worth. Case settled on confidential terms during trial.

Intellectual Property

Sensormatic Electronics Corp. v. The TAG Co., et al. (S.D. Fla., Fed. Cir. 2008-2010)
Trial counsel for plaintiff Sensormatic Electronics Corporation in patent infringement, trade secret misappropriation and breach of contract suit. Following a three-week bench trial, the Court entered judgment in favor of Sensormatic on all counts and entered a permanent injunction, all affirmed by the Federal Circuit. 

Applied Medical Resources Corp. v. United States Surgical Corp. (C.D. Cal., Fed. Cir. 2005-2009)
Trial counsel for defendant United States Surgical Corporation, a subsidiary of Covidien, in medical device patent infringement suit in which Applied Medical sought $300 million and an injunction. Won non-infringement jury verdict after five-week trial, which was affirmed on appeal in the Federal Circuit.  

Alexsam v. IDT (E.D. Tex. 2011, 2013)
Trial counsel in patent infringement case involving point-of-sale gift and phone card activation technology. Despite the court having deemed that roughly half the accused products were infringed as a discovery sanction based on issues pre-dating Bartlit Beck’s involvement, the trial team won a finding of no willfulness and limited the damages verdict to half of what plaintiff sought. The case is on appeal and in post-verdict proceedings in the trial court.

ICE Corp. v. Hamilton Sundstrand Corp. et al. (10th Cir. 2010-2011)
Appellate counsel for Hamilton Sundstrand and Ratier-Figeac in appeal of adverse jury verdict on a Kansas misappropriation of trade secrets claim. Obtained reversal of $9 million punitive damages award before the Tenth Circuit and prevailed on remand before the district court. Case settled on confidential terms.   

Honeywell International, Inc. v. Hamilton Sundstrand Corp. (D. Del. 2005)
Trial counsel for defendant United Technologies’ Hamilton Sundstrand division in patent infringement trial in Delaware. Honeywell alleged that Hamilton Sundstrand infringed an airplane engine patent and sought $135 million in damages. Jury verdict in the client’s favor, finding no infringement and that asserted patent was invalid.

Products Liability and Mass Tort

Lead Paint Litigation (2005-2010)
Trial and appellate counsel for defendant NL Industries in trial and appellate proceedings in Rhode Island. The AG sued to declare past sale of lead paint a “public nuisance” throughout State of Rhode Island, seeking compensatory and punitive damages as well as abatement. In a landmark decision, the Supreme Court of Rhode Island in June 2008 ordered dismissal of the AG’s lawsuit after nine years of litigation, resulting in a complete defense victory.    


United States v. Taylor (D.D.C. 2003)
First-chair trial counsel for federal criminal defendant facing ten years in prison for narcotics trafficking and firearms offenses. The government dismissed the case with prejudice following briefing and argument of motion to suppress.

United States v. Johnson (D.D.C. 2003)
First-chair trial counsel for federal criminal defendant facing fifteen years in prison for firearms offense. The district court granted motion to suppress and the government dismissed case with prejudice.

United States v. Anderson (D.D.C. 2002-2003)
First-chair trial counsel for federal criminal defendant facing up to five years in prison for firearms offense. Tried case to jury verdict, winning favorable sentencing determination.

United States v. Jones(D.D.C. 2003)
Second chair trial counsel for federal criminal defendant facing multiple years in prison for drug and firearms offense. Won jury verdict of not guilty on firearms charge. Sentenced to time served.   

Other representative cases


US Airways v. Sabre, et al. (S.D.N.Y. 2011-present)
Trial counsel for Sabre in federal antitrust suit brought by U.S. Airways in New York alleging unlawful monopolization, conspiracy and illegal contractual arrangements and seeking over hundreds of millions in damages. Discovery complete, summary judgment motions pending.

Oil and Gas

Ideal Royalty Class Action (Santa Fe, N.M., D.N.M., 2014-present)
Trial counsel for defendant Burlington Resources Oil & Gas Company, a subsidiary of ConocoPhillips, in a certified class action alleging underpayment of royalties on coal bed methane gas in New Mexico’s San Juan Basin. Case resolved shortly before trial after Bartlit Beck became involved.

Li, et al. v. ConocoPhillips Co.(S.D. Tex. 2012-present)
Lead trial counsel for ConocoPhillips in tort action brought by multiple Chinese fishermen plaintiffs for alleged harm from a June 2011 oil release from the Penglai-19-3 offshore oil field operated by ConocoPhillips China in Bohai Bay, China. ConocoPhillips has moved to dismiss the claims on forum non conveniens and other grounds.

BP Oil Supply Co. v. ConocoPhillips Co. (Del. Super. Ct. 2010); ConocoPhillips Co. v. BP Oil Supply Co. (Harris Cty Tex. Ct. 2010)
Lead trial and appellate counsel for ConocoPhillips in crude oil buy-sell contract dispute with BP Oil Supply in Delaware and Texas state courts. Case resolved on confidential terms.

Intellectual Property

Tessera, Inc. v. AMD et al. (N.D. Cal., 2011-present)
Trial counsel for plaintiff Tessera in patent suit against multiple defendants alleging infringement of groundbreaking patents related to semiconductor packaging. Tessera has settled with all but one of the defendants (on confidential terms). Case currently in the summary judgment phase. 

Tyco Healthcare Group LP v. C.R. Bard, et al. (D. Del. 2009-2011)
Trial counsel for plaintiff Tyco Healthcare in patent suit alleging that Bard's SorbaFix and PermaFix hernia mesh fixation products infringe one of Tyco Healthcare's patents and that Bard's infringement has been willful. Case settled on confidential terms.

Rembrandt Data Technologies, LP v. ADT Security Services, Inc. et al.(E.D. Va. 2008-2009)
Trial counsel for defendant ADT in patent infringement lawsuit filed by Rembrandt against ADT and seven other defendants. Rembrandt alleged that various products and services provided by defendants infringed four patents related to dial-up modem technology. Case resolved on confidential terms.

Edge Capture L.L.C. et al. v. Citadel Investment Group, LLC et al. (N.D. Ill. 2007-2008)
Trial counsel for defendant Citadel, an investment group, in patent infringement suit brought by Edge Capture. Edge alleged that various Citadel trading strategies infringed two of Edge Capture’s trading system and method patents. Case resolved on confidential terms.

SanDisk Corp. v. Infineon Technologies AG (N.D. Cal. 2004-2007)
Trial counsel for Infineon in patent litigation involving flash memory devices. Infineon accused SanDisk's CompactFlash products of infringing two of Infineon's CMOS circuitry patents. Case resolved on confidential terms.

Products Liability and Mass Tort

Vioxx Litigation (2007-2009)
Counsel for Merck in state court cases brought in New Jersey and federal MDL by health insurance companies and health and welfare funds seeking reimbursement for payments insurance companies made for Vioxx. Plaintiffs were seeking billions in damages. Merck announced favorable settlement for $80 million.

General Commercial Litigation

LaPlant v. The Northwestern Mutual Insurance Company (Mil. Cty Ct.., E.D. Wis. 2011-present)
Trial counsel for defendant Northwestern Mutual in putative class action alleging breach of contract and breach of fiduciary duties in connection with certain annuity products. Won appeal regarding application of the Class Action Fairness Act in the Seventh Circuit. Plaintiff is currently seeking class certification in the federal district court.

Mercury Companies, Inc. et al. v. The First American Company et al. (D. Colo. 2008-2010)
Co-lead trial counsel for counter-defendant Fidelity National Financial, Inc. and four plaintiff title agents in breach of contract and tortious interference action. Case resolved on confidential terms.

Adelphia Comm's Corp. v. Deloitte & Touche LLP (Philadelphia Ct. Common Pleas 2006-2007)
Trial counsel for defendant Deloitte & Touche in multi-billion dollar accounting malpractice case brought by Adelphia, with third-party claims against the Rigas family. Case resolved on confidential terms.

LSI Logic Corp. v. Broadcom Corp. et al. ( Colo. D. Ct. 2005)
Trial counsel for defendant Broadcom Corporation and seven of its employees in suit by LSI Logic alleging trade secret misappropriation, improper solicitation, breach of contract, and tortious interference. Case resolved for $0.

Pro Bono

Holte et al. v. Titan Chair et al. (D. Colo. 2010)
Lead trial counsel for small business owner plaintiff in patent infringement and false advertising lawsuit against company selling cheap knockoffs of plaintiff's products. Case resolved on confidential terms.

State v. Peters (Douglas Cty. Ct. 2005-2006)
Lead trial counsel representing defendant in criminal trial in Douglas County Court in Colorado. Defendant charged with seven criminal counts. Case resolved by favorable plea deal during trial.