Delbanco was born in London, England, the son of German Jewish parents Barbara (née Bernstein) and Kurt Delbanco, a businessman, art dealer, and sculptor.

In 2015, he published The Art of Youth: Crane, Carrington, Gershwin, and the Nature of First Acts.

In 2016, he published the Omnibus collection, Dear Wizard: The Letters of Nicholas Delbanco and Jon Manchip White.

[10] Simon made a comment about the subject's identity as a guest artist on Janet Jackson's 2001 single, "Son of a Gun (I Betcha Think This Song Is About You)", which sampled "You're So Vain".

Simon said about the song, "The apricot scarf" was worn by Delbanco.