Conversation so far:
Where was Yip Harburg born?
Yip Harburg was born in Isidore Hochberg on the Lower East Side of New York City on April 8, 1896.
How did Yip Harburg get his name?
Yip Harburg later adopted the name Edgar Harburg, and came to be best known as Edgar Yip Harburg.
Did Yip Harburg attend college?
After World War I, Harburg returned to New York and graduated from City College, which Ira Gershwin had initially attended with him, in 1921.

Question: What was Harburg's first job?
Self-contained rewrite: What was Yip Harburg's first job?