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

Leo has represented clients in commercial disputes in state court proceedings and arbitrations. He has litigated breach of contract and intellectual property disputes in federal district courts in the United States, and trademark disputes in opposition and cancellation proceedings before the Trademark Trial and Appeal Board of the U.S. Patent and Trademark Office. He also advises clients on all aspects of the branding process, including trademark prosecution..., licensing, and enforcement, as well as limited aspects of the corporate formation. 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 received a Master’s degree in intellectual property management from a Korean educational institution.


  • 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.
  • 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. Case pending before the Northern District of California.
  • 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.
  • 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 2012 and 2019 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.
  • Confidential JAMS Arbitration (JAMS Cal.) – 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.
  • 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 Virginia Super Lawyer — Civil Litigation (Rising Star)


  • 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


  • Virginia
  • DC
  • U.S. District Court Eastern District of Virginia
  • U.S District Court Eastern District of Wisconsin
  • U.S. District Court District of Columbia

Memberships &

  • Loudoun County Bar Association
  • Korean American Bar Association – DC, Treasurer/Secretary (2020 – Present)
  • Overseas Korean Traders Association, Washington D.C., Associate Member

Intern Program

As part of our effort to recruit, develop and retail the best and brightest attorneys, Dunlap Bennett & Ludwig offers a summer intern program for promising law school students who are looking to work as part of an innovative and incredibly successful team. With a global team of lawyers, selected candidates are able to work on high level projects in a collaborative space.

Paralegals and Legal Support Staff

At Dunlap Bennett & Ludwig, our team of paralegals and staff work together collaboratively along side our attorneys toward a common goal. We have created a positive work environment where our paralegals and legal assistants work to successfully reach firm-wide goals and support each other to combine individual strengths to enhance team performance. They regularly assist our attorneys with organizing and maintaining files, conducting legal research, and preparing documents.