Education & Honors

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

Articles Editor, Michigan Law Review

Darrow Scholar & Bates Memorial Award

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, 2015-2020

Bar admissions



Professional activities and community service

Board of Trustees, Minds Matter of Denver

Sean C. Grimsley

Denver Office
1801 Wewatta Street
Suite 1200
Denver, CO 80202
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Professional Practice

During his 15 years at Bartlit Beck and two years as an Assistant Federal Public Defender, Sean has spent thousands of hours in court and arbitration hearings trying cases, arguing motions, and presenting appeals. In the past five years, Sean has first-chaired a $100+ million CPR arbitration (pending); second-chaired a two-month antitrust trial in SDNY in a case where plaintiff sought $1+ billion but obtained a liability verdict on only one claim for 1% of its damages demand; co-first chaired the AAA arbitration defense of an independent oil company in a $25+ million securities fraud dispute where the claimant received nothing and was ordered to pay our client’s attorneys’ fees; co-first chaired a damages-only trial for defendant Sonitrol in which the jury adopted our client’s damages proposal (approximately 10% of the plaintiff’s demand) and successfully defended that verdict on appeal.

In 2010, Sean was also appointed to serve as Deputy Chief Counsel to the U.S. President’s National Commission on the BP Deepwater Horizon Oil Spill where he and his colleagues investigated the root causes of the spill. The hearing where Sean and the team presented its initial findings to the Commission can be seen at, and the Chief Counsel's report setting forth the team’s ultimate findings can be found here. Sean subsequently served as counsel and advisor to a major U.S. oil company regarding a 2011 oil spill in Chinese territorial waters. Sean regularly speaks to in-house law departments about the management and risk assessment failures that led to the BP oil spill.

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 serving as trial and appellate counsel for indigent criminal defendants in federal court in Washington, D.C. where he served as lead counsel in over 100 matters. He graduated summa cum laude from Michigan Law School in 2000 after obtaining B.A.s in Plan II Honors and Biology from the University of Texas. He lives in Denver with his wife Emily and their three wonderful (most of the time) children.

Cases tried or otherwise taken to judgment

Confidential CPR Arbitration (2018-2019)
Lead trial counsel for claimant oil company in $100+ million breach of warranty and breach of contract dispute, including three-week arbitration hearing in December 2019. Decision pending.

U.S. Airways v. Sabre Inc. (S.D.N.Y. 2013-present)
Second chair trial counsel for Sabre in antitrust action relating to contract between U.S. Airways and Sabre concerning Sabre’s Global Distribution System (GDS). US Airways sought $1.4 billion in trebled damages. Two-month jury trial resulting in defense verdict on one claim and elimination of 99% of damages on second claim. Sean took 12 out of 24 witnesses who testified live at trial, including cross-examining two of US Airways’ experts, and delivered an interim closing argument. Before trial, the team won motions to dismiss monopolization and declaratory judgment claims, for summary judgment dismissing US Airways’ claim for injunctive relief and over 75% of its damages claim, and for $6 million in costs/attorneys’ fees. Appeal currently pending.

Confidential AAA Arbitration 
Co-lead trial counsel for small independent exploration and production company in commercial and state securities law dispute. Claimant sought more than $25 million. After two-week hearing in June 2016, panel ordered claimant recover nothing and pay our client’s attorney’s fees.

Core-Mark v. Sonitrol (Adams Cty, Ct. Co. Ct. Appeals 2014-2016)
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. Before Bartlit Beck got involved, a previous jury found that Sonitrol had willfully and wantonly breached its burglar-alarm monitoring contract by failing to detect three burglars who looted plaintiffs' warehouse and eventually lit fires that ultimately destroyed the building. The jury awarded plaintiffs the damages number sponsored by Sonitrol, which was roughly 10% of what plaintiffs were seeking. Affirmed on appeal.

Confidential AAA Arbitration (2014-2015)
Second-chair trial counsel for “Big Four” accounting firm in AAA arbitration against hotel developer. Plaintiff alleged accountants’ negligence in advising on ESOP and other tax issues. Case settled favorably during trial after cross-examination of Plaintiffs’ witnesses.

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.

Alexsam v. IDT (E.D. Tex. 2011, 2013)
Second-chair trial counsel for defendant in patent infringement case involving point-of-sale card activation technology. Despite the court having deemed that roughly half the plaintiff’s products were infringed as a discovery sanction against the defendant prior to Bartlit Beck’s retention, the trial team won a finding of no willfulness and limited the damages verdict to half of the amount plaintiff sought. Co-lead trial counsel in subsequent post-verdict damages bench trial. Case settled on confidential terms after the Federal Circuit reversed one of the infringement findings.  

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.  

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.

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.

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.

Other representative cases

Oil and Gas

Ideal and Smith Royalty Class Actions (Santa Fe, N.M., D.N.M., 2014-2018)
Co-lead trial counsel for defendants ConocoPhillips and Burlington Resources Oil & Gas Company in separate $100+ million class actions alleging underpayment of royalties on coal bed methane gas in New Mexico’s San Juan Basin. Cases resolved shortly before trial after Bartlit Beck was retained.

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

Sycamore IP v. AT&T et al. (E.D. Tex., Fed. Cir., 2017-present)
Co-lead trial counsel for plaintiff Sycamore IP in $100+ million infringement action involving transcoding technology against AT&T, CenturyLink, Level 3, and Verizon. Case settled with Verizon shortly before trial. Cases against the remaining defendants are currently on appeal from a summary judgment decision of non-infringement.

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). Cases against all but one defendant settled on confidential terms.

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.


LaPlant v. The Northwestern Mutual Insurance Company (Mil. Cty. Ct.., E.D. Wis. 2011-2016)
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. Cased subsequently settled.

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.

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.