Attorneys William P. O’Sullivan

Print this page

attorney photo for print
shareholder | Manchester, NH

Bill serves as Chair of the Intellectual Property Law practice group. He advises clients on intellectual property protection strategies with a particular emphasis on patent prosecution and related counseling, risk analysis, and mitigation. Bill has experience working with a wide range of inventions involving electrical, mechanical, optical, computer hardware, and computer software technologies. Recently, he has worked on protecting inventions in computer-aided design, engineering, and simulation, network security, artificial intelligence, neural networks, home security cameras and monitoring systems, instant self-heating and self-chilling product technologies and packaging, industrial sand handling equipment, internal combustion engines, cycling shoes, weightlifting and exercise equipment, gaming, and in many other areas.

Bill believes that building relationships is a key part of providing good counseling, and he draws on his years of experience advising innovative and creative people at all kinds of large, mid-sized, and small companies, start-ups, and educational institutions, and individually. He also supports intellectual property licensing, litigation, due diligence, and provides some trademark counseling.

Bill has spoken on a variety of intellectual property topics, with a particular emphasis on patent law, in a variety of business and academic settings. Prior to joining Sheehan Phinney, he was a Principal in the New York office of Fish & Richardson, P.C. Prior to entering the legal field, Bill spent several years working as an electrical engineer, primarily in the maritime industry, and then as a Senior Project Manager for Design and Construction at New York University Medical Center.


  • State of New Hampshire
  • State of New York
  • State of New Jersey
  • U.S. Patent & Trademark Office

Civic Involvement

  • Swim Committee Member, Volunteer, and Competitor, Swim with a Mission, Inc.
  • Member, New Hampshire Bar, Intellectual Property section
  • Member, NH Tech Alliance, Product of the Year Committee
  • Judge, NH Tech Alliance, Entrepreneur of the Year Program


  • Rising Star by New England Super Lawyers®, Intellectual Property