[2] Upon discovering a hearing impairment, he left Europe to take a position as Professor of Music at the University of California at Berkeley, where he taught from 1912 to 1916 before being dismissed for his public opposition to U.S. entry into World War I.

His brother Alan Seeger was killed in action on July 4, 1916, while serving as a member of the French Foreign Legion.

Among Seeger's many specific interests were prescriptive and descriptive music writing[3] and determining the definition of what is meant by singing style.

[4] Along with composer Henry Cowell, ethnomusicologist George Herzog, Helen Heffron Roberts and Dorothy Lawton of the New York Public Library, Seeger was a founding member of the American Society for Comparative Musicology in 1933, the parent organization of the American Library of Musicology (ALM).

[8] They had three sons, Charles III (1912–2002), who was an astronomer,[9] John (1914–2010), an educator,[citation needed] and Pete (1919–2014), a folk singer.

[11] According to the ethnomusicologist Bruno Nettl, "Seeger played a unique and central role in tying musicology to other disciplines and domains of culture.