Greenburg wrote four series of children's books, The Zack Files, Secrets of Dripping Fang, Maximum Boy, and Weird Planet.
[3] His first piece of professional writing[citation needed] was "3 Bears in Search of an Author", a retelling of the same story in the voices of J.D.
[5] In September 1969, he published Porno-Graphics: The Shame of our Art Museums, a now scarce and far-out-of-print heavily illustrated book with lift-up vinyl page covers, pull-outs, and copies of famous paintings.
In a retrospective interview, Greenburg said, "At the time, I was amused by all the people who were being offended by anything slightly sexual.
'"[6] Greenburg is probably most well known for authoring a handful of very popular series of children's books, although he still also wrote novels for adults (mostly mysteries and thrillers).
He also wrote for television and movies, and has been regularly published in Life, Time, The New Yorker, and other national publications.
Greenburg has also written numerous sitcom pilots for CBS-TV and NBC-TV, including a fireman sitcom[citation needed] for producer-comedian Alan King, which Greenburg researched by spending months with NYC firefighters[citation needed], and a cop sitcom[citation needed] for producer Sonny Grosso, which Greenburg researched by spending months with NYC homicide cops.
With fellow author Avery Corman, Greenburg has also appeared as a stand-up comedian on television talk shows hosted by Sir David Frost, Dick Cavett, and Merv Griffin, and has performed at the New York Improv comedy club.
More than 150 of Greenburg's articles and humor pieces have appeared in such periodicals as The New Yorker, Playboy, The Huffington Post, Vanity Fair, New York, Esquire, The New York Times Magazine, The New York Times Book Review, Time, Life, Newsweek, Ms., Cosmopolitan, Mademoiselle, and Reader's Digest, and have been reprinted in dozens of anthologies of humor and satire in the U.S. and the United Kingdom.