David Leason


David Leason is a founding partner and has an extensive practice that focuses on patent prosecution and counseling.  David counsels clients in a broad spectrum of industries such as oil and gas, software, and medical technologies, and has done so for individuals, startups, and Fortune 100 companies. He advises clients in connection with software, robotics, mechanical and industrial systems, automotive technologies, medical devices, consumer electronics, and small appliances, other consumer products, and business methods. Whether he is engaged in developing an intellectual property portfolio, conducting due diligence reviews, or positioning clients to satisfy due diligence requests, David leverages his knowledge, creativity, and perseverance to maximize each client’s position. This is equally true when he is tasked with obtaining protection for a new idea, pursuing a licensing opportunity for a client, developing a litigation strategy, or identifying a non-infringing re-design to avoid a competitor’s patent claims. In alignment with his clients’ strategic business interests, David has helped clients mark their territory more clearly, whether to increase market share, hold competitors in abeyance, or complete an exit strategy involving a corporate acquisition.

The legal industry recognizes David for his thoroughly considered opinions on patentability, freedom-to-operate, infringement, and validity issues. He has been quoted in Law360 and described as a leader in the field by Intellectual Asset Management, among other publications. David has been an invited speaker at meetings of the Corporate Committee of the New York Intellectual Property Law Association, at a USPTO-sponsored workshop “Saturday Seminar” as part of an outreach to inventors, entrepreneurs, and small businesses, at Duke University and at the Practicing Law Institute. Before founding Leason Ellis in 2008, David worked at Darby & Darby, P.C., where he started as an associate after law school and went on to become a principal of that firm.

While in law school, David clerked for Judge Paul R. Michel of the United States Court of Appeals for the Federal Circuit, later Chief Judge (now retired), in connection with an Alexanders Fellowship Award from his
law school.

  • Benjamin N. Cardozo School of Law, J.D., 1992
  • University of Texas, M.S.E., Electrical Engineering, 1989
  • Duke University, B.S.E., Electrical Engineering and Computer Science, 1987
  • New York
  • Registered Patent Attorney: U.S. Patent and Trademark Office
  • U.S. District Court for the Southern District of New York
  • U.S. District Court for the Eastern District of New York
  • U.S. District Court of Appeals for the Federal Circuit
  • Darby & Darby, Procedures Chairman, 1992- 2008