1991- present Chairman of the Board, Ionis Pharmaceuticals, Inc.
1989- present Chief Executive Officer, Ionis Pharmaceuticals, Inc.
1998-2009 Adjunct Professor, Department of Biology, San Diego State University
1994-2004 Adjunct Professor, Department of Pharmacology, University of California, San Diego
1991-1992 Adjunct Professor, Department of Anatomy & Cell Biology, University of California, Los Angeles
1983-1988 Vice President, SmithKline Beckman Corporation
1982-1998 Adjunct Professor, Department of Pharmacology, Baylor College of Medicine
1982-1989 Adjunct Professor, Department of Pharmacology, University of Pennsylvania
1982-1988 President, Research & Development, Smith Kline & French Laboratories
1981-1988 Director, Molecular Pharmacology, Smith Kline & French Laboratories
1980-1982 Vice President, Research & Development, Smith Kline & French Laboratories
1979-1982 Associate Professor, Department of Pharmacology, Baylor College of Medicine
1979-1980 Clinical Associate Professor, Department of Medicine, Upstate Medical Center
1979-1980 Vice President and Associate Director, Research and Development, Bristol Laboratories
1977-1979 Clinical Assistant Professor, Department of Medicine, Upstate Medical Center
1977-1979 Associate Director of Research and Development, Bristol Laboratories
1976-1980 Director, Bristol-Baylor Molecular Pharmacology Laboratory, Baylor College of Medicine
1976-1979 Assistant Professor, Department of Pharmacology, Baylor College of Medicine
1976-1977 Clinical Instructor, Department of Medicine, Upstate Medical Center
1976-1977 Associate Director of Medical Research, Bristol Laboratories
1975-1976 Assistant Director of Medical Research, Bristol Laboratories
1974-1975 Internship, Baylor Medical School, St. Luke’s Program
1971-1990 Member, Cancer Research Center, Baylor College of Medicine
1971-1975 Instructor, Department of Pharmacology, Baylor College of Medicine
1971-1972 Postdoctoral Fellow, Department of Pharmacology, Baylor College of Medicine
1968-1971 Predoctoral Trainee, Department of Pharmacology, Baylor College of Medicine