John Craig Venter (born October 14, 1946) is an American scientist. He is known for leading one of the first draft sequences of the human genome and led the first team to transfect a cell with a synthetic chromosome. Venter founded Celera Genomics, the Institute for Genomic Research (TIGR) and the J. Craig Venter Institute (JCVI). He was the co-founder of Human Longevity Inc. and Synthetic Genomics. He was listed on Time magazine's 2007 and 2008 Time 100 list of the most influential people in the world. In 2010, the British magazine New Statesman listed Craig Venter at 14th in the list of "The World's 50 Most Influential Figures 2010". In 2012, Venter was honored with the Dan David Prize for his contribution to genome research. He was elected to the American Philosophical Society in 2013. He is a member of the USA Science and Engineering Festival's advisory board.

John Craig Venter was born in Salt Lake City, Utah, the son of Elisabeth and John Venter. His family moved to Millbrae, California during his childhood. In his youth, he did not take his education seriously, preferring to spend his time on the water in boats or surfing. According to his biography, A Life Decoded, he was said never to be a terribly engaged student, having Cs and Ds on his eighth-grade report cards. Venter considered that his behavior in his adolescence was indicative of attention deficit hyperactivity disorder (ADHD), and later found ADHD-linked genetic variants in his own DNA. He graduated from Mills High School. His father died suddenly at age 59 from cardiac arrest, giving him a lifelong awareness of his own mortality. He quotes a saying: "If you want immortality, do something meaningful with your life."

Although he opposed the Vietnam War, Venter was drafted and enlisted in the United States Navy where he worked as a hospital corpsman in the intensive-care ward of a field hospital. He served from 1967 to 1968 at the Naval Support Activity Danang in Vietnam. While in Vietnam, he attempted suicide by swimming out to sea, but changed his mind more than a mile out. Being confronted with severely injured and dying marines on a daily basis instilled in him a desire to study medicine, although he later switched to biomedical research.

Venter began his college education in 1969 at a community college, College of San Mateo in California, and later transferred to the University of California, San Diego, where he studied under biochemist Nathan O. Kaplan. He received a Bachelor of Science in biochemistry in 1972 and a Doctor of Philosophy in physiology and pharmacology in 1975 from UCSD.

After working as an associate professor, and later as full professor, at the State University of New York at Buffalo, he joined the National Institutes of Health (NIH) in 1984.

While an employee of the NIH, Venter learned how to identify mRNA and began to learn more about those expressed in the human brain. The short cDNA sequence fragments Venter discovered by automated DNA sequencing, he named expressed sequence tags, or ESTs. The NIH Office of Technology Transfer decided to file a patent on the ESTs discovered by Venter, patenting the genes identified based on studies of mRNA expression in the human brain. When Venter disclosed the NIH strategy during a Congressional hearing, a firestorm of controversy erupted. The NIH later stopped the effort and abandoned the patent applications it had filed, following public outcry.

Venter was passionate about the power of genomics to transform healthcare radically. Venter believed that whole genome shotgun sequencing was the fastest and most effective way to get useful human genome data. However, the method was rejected by the Human Genome Project, since some geneticists felt it would not be accurate enough for a genome as complicated as that of humans, that it would be logistically more difficult, and that it would cost significantly more.

Venter viewed the slow pace of progress in the Human Genome Project as an opportunity to continue his interest in trying his shotgun sequencing method to speed up human genome sequencing, so he sought funding from the private sector to start Celera Genomics. The company planned to profit from their work by creating genomic data to which users could subscribe for a fee. The goal consequently put pressure on the public genome program and spurred several groups to redouble their efforts to produce the full sequence. Venter's effort won him renown as he and his team at Celera Corporation shared credit for sequencing the first draft human genome with the publicly funded Human Genome Project.