John A. Castellano, III

Principal / Washington, D.C. Metro Office

John concentrates his practice on patent application preparation and prosecution in semiconductors, semiconductor processing, and semiconductor packaging, as well as telecommunications, consumer electronics, digital image signal processing, microelectronics, computer architecture, microwave reaction chambers, medical imaging, computer software and internet-related technologies, and GPS and satellite communications.

While attending law school, John developed computer programs for processing underwater acoustic signals.


John has lectured on U.S. patent prosecution and enforcement strategies at the Swedish Patent Office in Stockholm, Sweden; the Danish Patent Office in Copenhagen, Denmark; and the Swiss Patent Office in Bern, Switzerland. 

Awards & Distinctions

  • Managing Intellectual Property, “IP Stars,” 2014-2022


  • American Bar Association
  • American Intellectual Property Law Association
  • Harness IP Diversity & Inclusion Committee
  • Patent Lawyers Club of Washington, Past President


J.D., Patent Law, George Mason University, 1992

M.S., Electrical Engineering, George Washington University, 1987

B.S., Chemical Engineering, Lafayette College, 1983

Bar & Court Admissions


U.S. Patent and Trademark Office