Callahan, Harry (1912- ) , American photographer and teacher, whose highly personal, masterfully realized works have shaped modern photography. Callahan was born in Detroit, Michigan. After studying engineering at Michigan State University, he worked for Chrysler Motors from 1934 to 1944. He took up photography as a hobby in 1938 and in the 1940s began to produce photographs whose quality was recognized by other photographers. Influenced by Ansel Adams, Callahan's work is concerned with tone and texture.

In 1946 Hungarian-American artist László Moholy-Nagy invited Callahan to join the faculty of the Institute of Design in Chicago, and he became director of the department of photography in 1949. Callahan taught at the Institute until 1961, when he joined the Rhode Island School of Design where he headed the photography department from 1971 to 1973 and taught until 1977.

Callahan's works display his exquisite control over the composition, tones, and textures used to portray his subjects. Stark, disturbing photographs of people caught up in the pressures of city life are dramatized by Callahan's use of shadow and bright sunlight. His intimate photographs of his wife Eleanor and daughter Barbara are products of a loving husband and father and a masterful artist. His landscapes are often abstractions and exhibit the purity and simplicity he brings to all his work.

Callahan's photographs have been exhibited throughout the United States and Europe, including a retrospective exhibition at The Museum of Modern Art in 1976 and a show at the Venice Biennale in 1978. He has published numerous books, and his work has been recognized by honorary degrees and many awards, including a Guggenheim Fellowship in 1976.