In 1960 he emigrated from Norway to USA, and from then he worked in National Museum of Natural History for the Smithsonian Institution as an author and lecturer, now retired.

Dexter Sear at Insects.org states that '"The Butterfly Alphabet" is a great example of cultural entomology.'.

The book A World of Butterflies, with text by Brian Cassie and photographs by Kjell Sandved is described as an , his book The world of music is described by The Independent's Robert Fisk as "... a weighty heart attack of a book", and his book Leaves: The Formation, Characteristics, and Uses of Hundreds of Leaves Found in All Parts of the World is described by Tibor Fuchs as "Stunning photos and informative text about all kinds of leaves, including many that houseplant lovers have in their homes." in the City Room blog at New York Times written by the staff.

Kjell B. Sandved has published two encyclopedias and co-edited nine books.