Hyung Gyu (Leo) Sun

Senior Associate

Office: Leesburg, VA

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Biography

Hyung Gyu (Leo) Sun is a senior associate in the Leesburg office of Dunlap Bennett & Ludwig. Leo’s practice focuses on civil litigation and intellectual property.

Leo has represented clients in various commercial disputes in court and arbitration proceedings. As a versatile litigator, he handles all phases of litigation — from pleading and discovery through motion practice, mediation, settlement, and trial — in matters involving intellectual property infringement, breach of contract, breach of fiduciary duty, defamation, and other business tort claims in federal and state courts and before arbitral institutions.... He has extensive experience litigating trademark disputes before the Trademark Trial and Appeal Board of the U.S. Patent and Trademark Office, and advises clients on all aspects of the branding process, including trademark prosecution, licensing, and enforcement, as well as limited aspects of corporate formation and governance. He has additional experience representing clients in government contracting disputes before the Government Accountability Office and the U.S. Court of Federal Claims. Prior to joining the firm, Leo worked for a start-up company and an intellectual property law firm in Korea. In addition to his law degree, he holds a master’s degree in intellectual property management from a Korean university.

Experience

D’Antuono v. WireBarley America, Inc. et al. (E.D. Va.) – Counsel for third-party defendant in a wage dispute brought by former employees against an international money transfer company. Successfully defended the third-party defendant against multiple attempts by the company to join her in the litigation — first as a third-party defendant on claims of fraud and conspiracy, and later as a counterclaim defendant. Over two oral arguments and multiple rounds of briefing, moved to dismiss the third-party claims, which the court granted with prejudice, and subsequently opposed the company’s motions for leave to add the dismissed party as a counterclaim defendant, which the court denied.
SiteTools, Inc. v. Bansk Group LLC (C.D. Cal.) – Counsel for Bansk Group in a declaratory judgment and trademark cancellation action brought by an online provider of mortgage leads. Moved to dismiss the complaint on several grounds, including lack of personal jurisdiction. The court granted the motion to dismiss for lack of personal jurisdiction and the case was dismissed.
Guntaka v. Dataonez LLC et al. (Va. Cir. Ct.) – Counsel in a defendant-side commercial dispute where the plaintiff claimed breach of contract, wage law violations, and fraud, seeking damages in excess of $2.5 million. Prepared pretrial motions, took and defended depositions, and delivered opening statement. Case settled during trial after the parties’ opening statements.
Tangle, Inc. v. Buffalo Games, LLC (N.D. Cal.) – Counsel for Buffalo Games in a trademark and copyright infringement case brought by an international toy manufacturer. Moved to dismiss the complaint on several grounds, including lack of personal jurisdiction. The court granted the motion to dismiss for lack of personal jurisdiction with leave to amend the complaint. Subsequently defended jurisdictional discovery deposition and moved to dismiss the amended complaint. The court granted the renewed motion to dismiss and the case was transferred to the Western District of New York.
Briede Family Vineyard, LLC v. Quental, et al. (Va. Cir. Ct.) / Briede et al. v. Quental, et al. (Va. Cir. Ct.) – Counsel for two defendants in two related cases arising from alleged negative online reviews concerning a Virginia winery and an alleged covenant violation. In the individual plaintiffs’ case, multiple counts, including defamation and harassment by computer claims, were dismissed on demurrer and the sole remaining count was nonsuited by the plaintiffs shortly before trial. In the LLC’s case, demurred the sole count of conspiracy to injure in trade or business, which the court granted and the case was dismissed with prejudice.
Korea Advanced Institute of Science & Technology v. KIP Co. Ltd. et al (E.D. Wis.) – Counsel for KIP, KIPB, P&IB, and the CEO of P&IB in a breach of contract and fiduciary duty case brought by a South Korean national research university seeking damages arising out of the agreements between the university and KIP and between the university and P&IB. Moved to dismiss the complaint on several grounds, including forum non conveniens. The court granted the motion to dismiss for forum non conveniens and the case was dismissed. Read coverage on Law360 here: Judge Tosses $203M Korean IP Litigation Funding Row
Confidential Commercial Arbitration (LCIA) – Counsel for an affiliate of a leading computer software company that provides high-quality image solutions based on satellite utilization against an international space-to-cloud data and analytics company in several breach of contract matters. Case settled favorably.
Confidential Commercial Arbitration (JAMS) – Counsel for patent monetization companies against a law firm seeking over $28 million in damages. Plaintiff alleged it is entitled to a contingency fee payment concerning the patent litigation matter in which it partially represented one of the companies. Case settled favorably.
PCRX, LLC v. PCRx Computers Inc. (TTAB) – Counsel for PCRx Computers Inc. in a trademark opposition proceeding. Successfully defended PCRx Computers by moving to dismiss the opposition. The board granted the motion and the opposition was dismissed.
Titan Title, LLC v. Titan Title Group LLC (D.D.C) – Counsel for Titan Title, LLC in a trademark case alleging trademark infringement, false designation of origin, and unfair competition related to unauthorized usage of Titan Title’s trademark. Case settled favorably.
Throwdown Industries, Inc. v. Iron Army, LLC (TTAB) – Counsel for Throwdown in a trademark opposition proceeding. Successfully opposed Iron Army, LLC’s application to register THROWDOWN mark in connection with nutrition supplements. The Board granted Throwdown’s motion to quash Iron Army’s Notice of Deposition, Iron Army subsequently withdrew its trademark application, and the opposition was sustained.

Awards & Honors

2023-2025 Virginia Super Lawyer — Civil Litigation (Rising Star)

Education

BA, College of William and Mary, 2011
JD, Syracuse University College of Law, 2017
MA, Korea Advanced Institute of Science and Technology, 2014
MSL, Northwestern University School of Law, 2014

Admissions

State

District of Columbia
Virginia

Court

District of Columbia Courts
U.S. Court of Federal Claims
U.S. District Court for the District of Columbia
U.S. District Court for the Eastern District of Virginia
U.S. District Court for the Eastern District of Wisconsin
Virginia State Courts

Memberships &
Associations

Loudoun County Bar Association (2019-2021)
Korean American Bar Association – DC, Treasurer, Secretary, & Board Member (2020 – 2024)
Chartered Institute of Arbitrators, Associate Member (2025)
Overseas Korean Traders Association, Washington D.C.