John Cohen started to make films in 1962 in order to bring the music and the images together. Filmmaking provided a way to present traditional musicians in their home setting, to reveal the environment in which music happens, and suggests how music functions within its community. His earliest films (The High Lonesome Sound, The End of an Old Song, Sara & Maybelle: the Original Carter Family) were about Appalachian music in Kentucky, North Carolina and Virginia. He later surveyed a wide spectrum of American music in Musical Holdouts including black children in the Carolina Sea Islands, old time and bluegrass in Appalachia, cowboys in Arkansas, Indians in Oklahoma, and the counter-culture street musicians in Berkeley, California and New York.

He then started a series of films in the Andes of South America exploring the isolated community of Q'eros, its survival strategies, textiles, rituals and festivals. Later he did a broad survey of Andean music (Mountain Music of Peru) as it exists in both the highlands and coastal cities of Peru where the migrant communities have established themselves. In 1990 he made a film about Peruvian Huayno music, which is the popular "hillbilly" music of the Andean people that combines Inca musical scales and rhythms with Spanish instruments, and is performed on commercial records and popular radio shows throughout Peru.

He has done films about old ballad singing in Britain and Scotland which were meant as companions pieces to his Appalachian Ballad film (The End Of An Old Song). His film Post Industrial Fiddle looks at a Maine musician who works in the paper mills. His film Pericles In America follows a Greek clarinetist in his journeys between Astoria, Queens and Epirus, Greece.

In all these films Cohen examines the outlook of people at the lower end of the social structure who are known as the "folk" in academic language and the language of the upper classes, but a term never used by the people whose music it is. In all his films, the word folk never appears.

His films are distributed by the University of California Extension Center for Media and Independent Learning. They are in the collections of many universities, colleges and libraries across America. Thousands of his prints and videos are in circulation. His three early Appalachian films are available on home video collection That High Lonesome Sound through Shanachie Video, and his first Peruvian film, Q'eros: The Shape of Survival is available on home video through Mystic Fire Video.