Bill Weir was born in 1967 in Milwaukee, Wisconsin. He had a tough childhood; his parents divorced at an early age, and his mother, a devout Christian, moved him through 17 schools across six states, following what she believed were messages from God. Despite this, Weir completed high school and later earned a degree in journalism and creative writing from Pepperdine University in Malibu. 

He began his journalism career in 1991 as a general assignment reporter and sportscaster at KAAL in Austin, Minnesota, before working through local markets in Green Bay, Chicago, and Los Angeles. He then joined ABC News in 2004, co-anchoring the weekend edition of Good Morning America and later becoming co-anchor of Nightline in 2010. 

Bill Weir moved to CNN in 2013, joining the network as an anchor and Chief Innovation Correspondent. At CNN, he created and hosted The Wonder List with Bill Weir, a documentary series spanning 28 countries. In 2019, he was named CNN’s first Chief Climate Correspondent. He also won a News & Documentary Emmy in 2022 for his special Eating Planet Earth, and published his debut book, Life as We Know It (Can Be), in April 2024.