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Sean is a top trial lawyer and litigator in our Denver office. During fifteen years at Bartlit Beck and two years as a public defender, Sean Grimsley has spent thousands of hours in court and arbitrations trying cases, presenting motions, and arguing appeals. In the past six years, Sean has first-chaired a $100+ million CPR arbitration; second-chaired a ten-week trial in a $1 billion+ antitrust matter in S.D.N.Y.; co-first-chaired the AAA arbitration defense of an independent oil company in a $25+ million securities fraud dispute; and co-first-chaired a damages-only trial for defendant Sonitrol, including successfully arguing the appeal affirming the verdict. Sean and his team recently won a motion to dismiss on forum non conveniens grounds on behalf of client Arconic Inc. regarding wrongful death and products liability claims arising out of the Grenfell Tower fire in 2017.

In 2010, Sean was appointed to serve as Deputy Chief Counsel to the President's 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 http://www.c-spanvideo.org/seangrimsley, and the Chief Counsel's report setting forth the team's ultimate findings can be found here. Sean is also currently serving as Special Assistant Attorney General to the State of Colorado, assisting with the Colorado AG’s investigation of the Aurora Police Department and related entities.

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 spent two years as an Assistant Federal Public Defender in Washington, D.C., serving 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.

Representative Matters

Behrens et al. v. Arconic Inc. (E.D. Pa. 2019-present)
Lead trial counsel for Arconic Inc. in wrongful death and products liability mass action brought by 247 plaintiffs and their estates seeking damages arising out of the 2017 Grenfell Tower fire in London. Plaintiffs allege cladding panels made by Arconic's French subsidiary contributed to the rapid spread of the fire. Successfully removed the case to federal court and prevailed in the district court on motion to dismiss for forum non conveniens. Appeal pending. 

Climate Change Litigation (Multiple jurisdictions, 2019-present)
Lead national counsel for ConocoPhillips Co. in multiple suits around the country brought by state and local governments against industry alleging liability for and seeking damages related to climate change.

Sprint v. Cequel et al. (D. Del. 2020-present) 
Co-lead trial counsel for defendant Cequel (Altice) in patent lawsuit brought by Sprint alleging that Cequel’s voice-over-IP networks infringe a number of Sprint’s patents. Trial scheduled for 2021.

General Access Solutions, Ltd. v. Sprint et al. (E.D. Tex. 2019-present)
Co-lead trial counsel for plaintiff General Access in patent lawsuit accusing Sprint’s 4G LTE network of infringing beamforming patent. Trial scheduled for 2021.

EEOC v. FedEx Ground (W.D. Pa.)
Trial counsel for FedEx Ground in an enforcement action brought by the EEOC under the Americans With Disabilities Act. EEOC filed claims on behalf of roughly 300 deaf FedEx Ground package handlers from dozens of facilities around the country, alleging that FedEx Ground failed to provide a variety of reasonable accommodations to these employees, such as ASL interpreters at meetings. Bartlit Beck was brought in to take over the matter after nearly a decade of investigation, conciliation, and litigation with EEOC. Along with a team of lawyers from three different firms, Bartlit Beck crafted a strategy that led to a favorable settlement in May 2020, prior to a single deposition being taken. 

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 2018 and closing arguments in March 2019.

U.S. Airways v. Sabre (S.D.N.Y. 2013-present)
Co-lead trial counsel for Sabre in antitrust action relating to contracts between U.S. Airways (now American Airlines) and Sabre concerning Sabre's Global Distribution System. U.S. 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. Took twelve out of twenty-four live witnesses. Before trial, the team won a motion to dismiss monopolization and declaratory judgment claims, a motion for summary judgment dismissing U.S. Airways' claim for injunctive relief, and over 75% of its damages claim, and a motion for $6 million in costs/attorneys' fees. The Second Circuit subsequently vacated the jury's liability finding and remanded the case for a new trial. Re-trial scheduled for 2022.

Ideal and Smith Royalty Class Actions (Santa Fe, N.M., D.N.M. 2014-2018)
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. 

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 remain pending following summary judgment of non-infringement. 

Li, et al. v. ConocoPhillips Co. (S.D. Tex. 2012-2017)
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. Case dismissed on forum non conveniens and other grounds. 

Confidential AAA Arbitration (2016)
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 that claimant recover nothing and pay our client's attorneys' fees.

Core-Mark v. Sonitrol (Adams Cty. Ct., Colo. Ct. Appeals 2014-2016)
Co-lead trial counsel for 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 destroyed the building. On retrial, 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 plaintiff's witnesses.

American Airlines v. Sabre (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.

LaPlant v. The Northwestern Mutual Insurance Company (Milwaukee Cty. Ct., E.D. Wis. 2011-2016)
Co-lead trial counsel for 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.

Tessera, Inc. v. AMD et al. (N.D. Cal., 2011-2016)
Co-lead trial counsel for 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). 

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.

Tyco Healthcare Group LP v. C.R. Bard, et al. (D. Del. 2009-2011)
Lead 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.

Sensormatic Electronics Corp. v. The TAG Co., et al. (S.D. Fla., Fed. Cir. 2008-2010)
Trial counsel for 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.

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 the 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. 

Applied Medical Resources Corp. v. United States Surgical Corp. (C.D. Cal., Fed. Cir. 2005-2009)
Trial counsel for 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.

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.

Professional Activities and Community Service

Board of Trustees, Minds Matter of Colorado

Chair's Roundtable, Colorado Lawyers Committee

Education & Honors

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

Articles Editor, Michigan Law Review

Darrow Scholar & Bates Memorial Award Winner

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


  • Honorable Sandra Day O'Connor, United States Supreme Court, 2003-2004
  • Honorable Harry T. Edwards, Chief Judge, United States Court of Appeals for the District of Columbia Circuit, 2000-2001

Government Service

Special Assistant Attorney General for State of Colorado assisting with pattern and practice investigation of Aurora Police Department and related entities

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

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

Awards & Recognition

Recognized as National and Local Litigation Star by Benchmark Litigation

Named to Lawdragon's Top 500 Leading Lawyers in America

Named to Best Lawyers in America

Fellow, Litigation Counsel of America


  • Colorado
  • California
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