Paul A. Stone worked as a Patent Attorney for Senniger, Powers (St. Louis) from 1995-1998. Paul taught Patent Law as an Adjunct Professor for the University of Missouri Law school from 1997-1998. In 1998, he joined Symyx Technologies, Inc. (Santa Clara), and became Vice President and Chief Patent Counsel in 2003. Paul joined Ilypsa, Inc. (Santa Clara) in 2005, serving as Senior Vice President, General Counsel and Chief Patent Counsel, until the company was acquired by Amgen, Inc. in 2007.

Since then, Paul has been Senior Vice President, General Counsel, and Chief Patent Counsel at AllChemie, Inc. (San Francisco), a biopharmaceutical company. Paul has been an Adjunct Professor at Santa Clara University School of Law since 1999.