[3][4][5] Born in Anaheim, California, Berg was originally a farmer, but was inspired to enlist when he saw a sign indicating that the government was looking for people to fight fascism.

He began serving as a union organizer in the 1950s, and, in a 2007 interview, described the steps he took to discourage the attention of Federal Bureau of Investigation agents.

Berg became an official of the National Association for the Advancement of Colored People (NAACP), when he was elected the Vice President of the Stanislaus County branch.

[8] He was interviewed for an episode of the PBS show History Detectives to provide background about the experience of American volunteers when a segment was focused around an artifact from the Spanish Civil War.

[1][2][11][12] On March 25, 2016, approximately a month after Berg's death, United States Senator John McCain published an op-ed in The New York Times saluting him and his comrades, who had fought for the values they believed in, in Spain, and when they returned home to the U.S.[11]