Conversation so far:
Where did Duke Ellington get his first start?
At first, Duke Ellington played in other ensembles, and in late 1917 formed his first group, The Duke's Serenaders (Colored Syncopators, his telephone directory advertising proclaimed)
Are there any other interesting aspects about the Duke Ellington article?
Duke Ellington was also The Duke's Serenaders's booking agent. His first play date was at the True Reformer's Hall, where he took home 75 cents.
Did Duke Ellington have any other play dates?
Duke Ellington played throughout the D.C. area and into Virginia for private society balls and embassy parties.
Did Duke Ellington do any live performances?
In June 1923, Duke Ellington had a gig in Atlantic City, New Jersey and another at the Exclusive Club in Harlem. In September 1923, he moved to the Hollywood Club.
Did Duke Ellington tour in his early career?
What influenced Duke Ellington?
Although trumpeter Bubber Miley was a member of the orchestra for only a short period, he had a major influence on Duke Ellington's sound.
Did anyone aid Duke Ellington in his early career?
When his drummer Sonny Greer joined the Wilber Sweatman Orchestra in NYC, Duke Ellington left his successful career in D.C. and moved to Harlem, becoming part of the Harlem Renaissance.

Question: When did he do this?
Self-contained rewrite: When did Duke Ellington move to Harlem?