Kalischer was a member of ASPP (American Society of Picture Professionals); a member of One by One (an international dialogue group between survivors and perpetrators of the Holocaust) and worked as a freelance photographer of The New York Times, Newsweek, Life, Fortune, Du, The Sun, Yankee, Coronet, Country Journal, Moment, Vermont Life, In Context, Jubilee, Yes, Orion, Ploughshares, Common Ground, Architectural Forum, Places, Urban Design International, Progressive Architectural, and Time magazine.

His photograph of a little boy with his puppy at the base of apartment steps on the West Side, New York, was selected by Edward Steichen for the world-touring Museum of Modern Art exhibition The Family of Man exhibition, seen by 9 million visitors.

[2] His series of photographs of people arriving in New York City from displaced persons camps in post-World War II Europe, taken in 1947 and 1948, was his most recognized work.

[3] Many are included in Clemens Kalischer, edited by Denis Brudna and Norbert Bunge (Hatje Cantz).

His freelance work focused on music (The Marlboro Music Festival, The Lenox School of Jazz, South Mountain Music Festival, Tanglewood, and many more), the arts (Black Mountain College, Pilobolus, The Flaherty Film Seminar, The Berkshire Theater Group, and many more), architecture, farming (CSA's, Italian Piedmont, slow-food movement, Vermont, and more), nature, portraiture, images form the U.S. south, urban and rural areas of the U.S., images from Europe, India, Cuba, and Israel.