Devoted to understanding vernacular culture, he gathered and commented upon the speech, stories, songs, emblems, rituals, art, artifacts, memorials, and landmarks which constitute laborlore.

He joined the Civilian Conservation Corps and spent his year of service in a camp on the Klamath River as a road builder and firefighter.

Describing himself as an "anarcho-syndicalist with strong libertarian leanings," or a "left-libertarian,"[4] Green combined a sensitivity for working people, an abiding concern for democratic processes, and a pragmatic willingness to lobby for reforms.

In 1942 Green purchased the album Work Songs of the U.S.A. performed by folk singer Huddie "Leadbelly" Ledbetter.

His love of music and especially the song "Old Man" sparked his interest in folkloristics, but it was to be nearly two decades before he returned to formal academia.

In the same period he recorded "Girl of Constant Sorrow," an LP of songs sung by Sarah Ogan Gunning, the sister of coalminer, songwriter, and labor leader Jim Garland.

Green joined the University of Illinois at Urbana-Champaign in 1960, where he held a joint appointment in the Institute of Labor and Industrial Relations and the English Department until 1972.

Working as a senior staff associate at the AFL-CIO Labor Studies Center in the early 1970s, he initiated programs presenting workers' traditions at the Smithsonian Institution's Festival of American Folklife on the National Mall, and from 1969 to 1976 he left academia to live in Washington, D.C., where he led the successful legislative campaign to enact the American Folklife Preservation Act.

Green also brought together unionists, activists, scholars, and artists in "Laborlore Conversations," a series of conferences on working class culture.