Dr. Hood's research has focused on fundamental biology (immunity, evolution, genomics) and on bringing engineering to biology through the development of five instruments; the DNA and protein sequencers and synthesizers and the ink–jet oligonucleotide synthesizer (making DNA arrays) for deciphering the various types of biological information (DNA, RNA, proteins and systems). In particular, the DNA sequencer has revolutionized genomics by allowing the rapid automated sequencing of DNA, which played a crucial role in contributing to the successful mapping of the human genome during the 1990s and early 2000s.  These instruments constitute the technological foundation for modern molecular biology and genomics.  He has applied these technologies to diverse fields including immunology, neurobiology, cancer biology, molecular evolution and systems medicine.

Early in his career, he applied these technologies to the study of molecular immunology (and discovered many of the fundamental mechanisms for antibody diversity) and neurobiology (he cured the first neurological disease by gene transfer in mice).  In the late 1980s he realized that to really understand immunology, it would require a systems approach, thus, he began thinking about systems biology. 

In 1992, Dr. Hood moved to the University of Washington as founder and Chairman of the cross–disciplinary Department of Molecular Biotechnology (MBT) and developed the ink–jet oligonucleotide synthesizer which synthesized DNA chips. At MBT he initiated systems' studies on cancer biology and prion disease. In 2000, he co–founded the Institute for Systems Biology in Seattle, Washington, to more effectively continue pioneering systems approaches to biology and medicine. Here he has contributed seminal papers to delineating the systems approach to biology and disease and to pioneer developing new technologies (microfluidics/nanotechnology and molecular imaging) in collaboration with colleagues at Caltech.  Dr. Hood is now pioneering the idea that the systems approach to disease, the emerging technologies, and powerful new computational and mathematical tools will move medicine from its current reactive mode to a predictive, preventive, personalized and participatory mode (P4 medicine) over the next 5-20 years.

Dr. Hood was awarded the Lasker Prize in 1987 for his studies on the mechanism of immune diversity. Dr. Hood was also awarded the 2002 Kyoto Prize in Advanced Technology for the development of the five different instruments.  He received the 2003 Lemelson–MIT Prize for Innovation and Invention for the development of the DNA sequencer. Most recently, Dr. Hood's lifelong contributions to biotechnology have earned him the prestigious 2004 Biotechnology Heritage Award, as well as the 2003 Association for Molecular Pathology (AMP) Award for Excellence in Molecular Diagnostics for his pioneering efforts in molecular diagnostics.  In 2006 he received the Heinz Award in Technology, the Economy and Employment, for his extraordinary breakthroughs in biomedical science at the genetic level. In 2007 he was elected to the Inventors Hall of Fame (for the automated DNA sequencer) and in 2008 he received the Pittcon Heritage Award for helping to transform the biotech industry.  Dr. Hood has received 17 honorary degrees from Institutions such as Johns Hopkins, Yale, UCLA, and Whitman College.  He has published more than 650 peer-reviewed papers, received 15 patents, and has co–authored textbooks in biochemistry, immunology, molecular biology, and genetics, and is just finishing a textbook on systems biology. In addition, he coauthored with Dan Keveles a popular book on the human genome project–The Code of Codes. 

 Dr. Hood is a member of the National Academy of Sciences, the American Philosophical Society, the American Association of Arts and Sciences, the Institute of Medicine and the National Academy of Engineering.  Indeed, Dr. Hood is one of only 7  (of more than 6000 members) scientists elected to all three academies (NAS, NAE and IOM).  Dr. Hood has also played a role in founding more than 14 biotechnology companies, including Amgen, Applied Biosystems, Systemix, Darwin and Rosetta.  He is currently pioneering systems medicine and the systems approach to disease and has recently cofounded the company Integrated Diagnostics—that hopefully will become a platform company for P4 medicine.

Dr. Hood has had a life–long commitment to K–12 science education and has a major effort at ISB in this regard.  Dr. Hood enjoys reading, mountaineering, cross-country skiing, sea kayaking and exercise.