A lay analyst and early follower of Carl Jung, Oppenheim was also a founder and editor of The Seven Arts.
His poetry followed Walt Whitman's model of free verse ruminations on "social and democratic aspects of life".
[2] Oppenheim depicted labor troubles with Fabian and suffragist themes in his novel, The Nine-Tenths (1911) and in his famous poem Bread and Roses (1911), inspired by a speech given by Helen Todd.
Oppenheim's published works include Monday Morning and Other Poems (1909); Pay Envelopes (1911); The Nine-Tenths (1911); The Olympian (1912); Idle Wives (1914); Songs For The New Age (1914); The Beloved (1915); War and Laughter (1916); The Book Of Self (1917); The Solitary (1919); The Mystic Warrior (1921); Golden Bird (1923); The Sea (collected poetry – 1924); Behind Your Front (1926); and American Types: A Preface To Analytic Psychology (1931).
At The Seven Arts magazine he served as primary editor[1] and worked with Waldo Frank, George Jean Nathan, Louis Untermeyer and Paul Rosenfeld from 1916 to 1917, until he was blacklisted[by whom?]
due to his opposition to US entry into World War I. James Oppenheim later wrote a reminiscence of his one tumultuous year as editor of the journal in which he observed that Randolph Bourne "was the real leader ... of what brains and creativeness we had at the time and had he lived the 'twenties might have sparkled much more than they did.
It was something in those days to know one was shadowed, spied upon, trailed by snoopers, that one must whisper what one thought in a restaurant and even then be sure one's friend wasn't going to hand one over to the police. ...
"[5] Notable writers who contributed to the magazine under his guidance included Sherwood Anderson, Van Wyck Brooks, Max Eastman, Robert Frost, D. H. Lawrence, Vachel Lindsay, Amy Lowell, and Lala Lajpat Rai.