After serving for more than a decade as Editor-and-Chief of The New York Observer, he held an executive position within the fashion magazine division of Fairchild Publications. He is perhaps best remembered for his key role in bringing journalism into the digital era.
While studying at Harvard University, he roomed with one of the sons of Robert F. Kennedy. After graduating from college, Kaplan worked for Esquire, Manhattan, Inc., and The New York Times.
He edited a New York Observer anthology titled The Kingdom of New York.
With his first wife, Audrey Walker, he had children named Peter, Caroline, and Charlie. His second marriage, to Lisa Chase, produced a son named Davey.
In a 2009 episode of The Charlie Rose Show, he discussed the effects of the internet and mobile devices upon journalism.