Alex Webb became interested in photography during his high school years and attended the Apeiron Workshops in Millerton, New York, in 1972. He majored in history and literature at Harvard University, at the same time studying photography at the Carpenter Center for the Visual Arts. In 1974 he began working as a professional photojournalist and joined Magnum Photos as an associate member in 1976.
Webb received a New York Foundation for the Arts Grant in 1986, a National Endowment for the Arts Fellowship in 1990, a Hasselblad Foundation Grant in 1998 and a Guggenheim Fellowship in 2007. 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 in the United States and Europe, in museums including 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.