McCormick was responsible for discovering and protecting material by Blind Lemon Jefferson, Lead Belly and many others, and he's credited with giving Lightnin' Hopkins' career a new lease of life.

He started out as an archivist of popular culture in Ohio, before being hired in 1946 to research the last two volumes of a jazz compilation. That led to a fascination with the blues, and the building of an archive collected from nearly 1000 counties.