John S. Watson was born in California in 1956. In 1978, he graduated with a B.A. in Agricultural Economics from the University of California, Davis, and in 1980 he received an MBA from the University of Chicago Booth School of Business.
In 1980, he joined the Chevron Corporation. He served as its Chief Financial Officer from 2001 to 2005. From 2009 to 2010, he was Vice-Chairman of the Board. Since 2010, he has served as Chairman and CEO.
He also serves as Chairman of the Board of the American Petroleum Institute, and on the Board of Directors of Caltex, Dynegy (2001–2004), the National Petroleum Council, the Business Council, the Business Roundtable, JPMorgan International Council, the American Society of Corporate Executives, and the Animal Rescue Foundation.
In October 2014 Rainforest communities in Ecuador requested that the International Criminal Court open a criminal investigation of John Watson over his role in violating international humanitarian law by obstructing a court-mandated clean-up of toxic contamination in the Amazon, putting thousands of lives at risk.  This was contrary to the fact that on March 4, 2014, the U.S. District Court for the Southern District of New York ruled that the $9.5 billion Ecuadorian judgment was the product of fraud and racketeering activity, finding it unenforceable.