Manufacturers agent firm Arthur G. Henderson & Associates, Pittsburgh, 1957-1959. Patent agent Swift & Company, Washington, 1959-1962. Law clerk to Honorary Donald E. Lane United States Court Claims, 1962-1963.
Associate Irons, Birch, Swindler & McKie, 1963—1965. Founding partner Finnegan, Henderson, Farabow, Garrett and Dunner LLP, since 1965. Advisory council United States Court Federal Claims, 1982-2006.
Legal advisory board Martindale-Hubbell/Lexis Nexis, 1996-2009, intellectual property advisory board, 2007-2009.
Board advisors., distinguished alumni George Washington University Law School. Fellow: American Bar Foundation (life). Member: American Bar Association (house of deals 1999—2005, advisory panel since 2006), American Arbitration Association (panel of neutrals, national patent advisory council), United States Court Federal Claims Bar Association (board directors 1987-1990, founder 1987), Supreme Court History Society, Intellectual Property Owners Association (Education Foundation, board dirs since 2008), International Trademark Association, American Intellectual Property Law Association, United States Chamber of Commerce (chairman patent, trademark and copyright council 1980-1982), International Trade Commission Trial Lawyers Association (founder 1984), Bar Association District of Columbia (chairman Court Claims committee 1973-1974, chairman patent, trademark and copyright law section 1974-1975, board directors 1975-1976, trustee research foundation 1980-1981, chairman Court Appeals for Federal Circuit Committee 1982-1983), Federal Circuit Bar Association (founder 1985, board directors 1985-1986, member judicial selection committee 1990—2009, board dirs 1996-1999), District of Columbia Bar Association, Virginia State Bar, Virginia Bar Association, International Bar Association, Capital Society of Clubs, TPC Potomac at Avenel Farms, City Club of Washington (board governors 1990-1995), University Club, Burning Tree Club, Congressional Country Club, Delta Theta Phi, Phi Gamma Delta.