Alex Webb was born in San Francisco, California in 1952. He became interested in photography during his high school years and attended the Apeiron Workshops in 1972. He majored in history and literature at Harvard University, studying photography at the Carpenter Center for the Visual Arts. In 1974 he began working as a professional photojournalist and his photographs started to appear in such publications as the New York Times Magazine, Life, Geo, Stern, and National Geographic. Webb joined the international photographers cooperative Magnum Photos as an associate member in 1976.

During the mid-1970's, Webb photographed in the US south, documenting small town life in black and white. He also began working in the Caribbean and Mexico. In 1978 he started photographing in color, which he has continued to do to the present. He has published five books: Hot Light/Half-Made Worlds (1986), Under A Grudging Sun (1989), From the Sunshine State (1996), Amazon: From the Floodplains to the Clouds(1997), and Crossings (2003). He has also created a technology-mediated artist's book entitled Dislocations with the Film Study Center at Harvard University (1998-99). His book Istanbul: City of 100 Names, is scheduled to be published in 2007.

Webb received a New York Foundation of the Arts Grant in 1986, a National Endowment for the Arts Fellowship in 1990, and a Hasselblad Foundation Grant in 1998. He won the Leopold Godowsky Color Photography Award in 1988, the Leica Medal of Excellence in 2000, and the David Octavius Hill award in 2002. His photographs have been the subject of articles in Art in America and Modern Photography. He has exhibited widely both in the United States and Europe. Among museums that have exhibited his work are: the Walker Art Center, the Museum of Photographic Arts, the International Center of Photography, the High Museum of Art, the Museum of Contemporary Art San Diego, and the Whitney Museum of American Art.