[1] Upon graduation from City College, Berenberg was employed as a public school teacher, a vocation which he continued from 1913 until 1918, when he resigned his post under fire for his socialist political views.
[1] At the end of the 1920s, Berenberg went into partnership with a friend named Clifford Hall and purchased a college preparatory school in New York City called The Franklin School, an academy which specialized in helping to place Jewish boys from less-than-elite families into Ivy League colleges.
[1] He remained in this position until 1921, working after that date as a teacher on site at the Rand School, conducting classes in English, History, and various topics related to Socialism.
Ruthenberg, Alexander Stoklitsky, and Nicholas Hourwich — against an equally organized faction of "Party Regulars" led by Executive Secretary Adolph Germer, James Oneal, and Julius Gerber, Berenberg found himself solidly in the latter camp.
January 1932 saw the launch of a new publication, the realization of David P. Berenberg's dream — The American Socialist Quarterly.
[4] Berenberg was a frequent contributor to The Socialist Call, the weekly newspaper established by the Left Wing opposition to the Old Guard in 1935.
"[5] Berenberg seems to have been discouraged from radical politics by the bitter factional struggle and series of splits which decimated the Socialist Party in 1936 and 1937.
His last political pamphlet was published in 1934 and his name was removed from the masthead of The American Socialist Monthly effective with the May 1937 issue.
Thereafter, Berenberg retired and moved to Long Island, where he stayed intellectually engaged by conducting literary book clubs.