William Henry Gates III, known as Bill Gates, is an American businessman and philanthropist best known for co-founding the software company Microsoft with his childhood friend Paul Allen. He held various positions at Microsoft, including chairman, chief executive officer (CEO), president, and chief software architect. Gates was Microsoft's largest individual shareholder until May 2014 and was a pioneer in the microcomputer revolution of the 1970s and 1980s.

In June 2008, Gates transitioned into a part-time role at Microsoft to focus on the Bill & Melinda Gates Foundation, a private charitable foundation he and his then-wife Melinda established in 2000. He stepped down as chairman of the Microsoft board in February 2014 to become a technology adviser, supporting CEO Satya Nadella, and left his board positions at Microsoft and Berkshire Hathaway in March 2020 to dedicate himself to philanthropy, particularly in areas including climate change, global health and development, and education.

Born and raised in Seattle, Washington, Gates and Allen founded Microsoft in Albuquerque, New Mexico, in 1975. He led the company as CEO until January 2000 and remained chairman of the board of directors while becoming chief software architect. Gates faced criticism during the late 1990s for business tactics deemed anti-competitive.

Since 1987, Gates has featured in the Forbes list of the world's top billionaires. Holding the title of the wealthiest person globally from 1995 to 2017, except in 2008 and from 2010 to 2013, he became the first centibillionaire in 1999. His post-Microsoft endeavors include founding and chairing companies such as BEN, Cascade Investment, TerraPower, Gates Ventures, and Breakthrough Energy. Gates has generously donated to various charitable organizations and scientific research programs through the Bill & Melinda Gates Foundation. This foundation spearheaded a significant vaccination campaign, greatly contributing to eradicating the wild poliovirus in Africa. In 2010, Gates and Warren Buffett initiated the Giving Pledge, encouraging billionaires to allocate at least half their wealth toward philanthropy.