Tonchi is currently the editor of T: The New York Times Style Magazine. He will take over as the editor-in-chief of W on 12 April.
Tonchi said he plans to make W more accessible by shaping it up as a general-interest magazine than one that is obsessed with fashion.
Advance Publications, which owns Conde Nast and Fairchild, has said it would be moving W from the trade-oriented Fairchild to the consumer-driven Conde Nast.
Tonchi, who joined The New York Times as style editor in 2003, previously worked with Esquire and the Conde Nast publications Self and L'Uomo Vogue.
Advertising pages at W fell by almost 50 per cent between 2008 to 2009, according to a media industry newsletter.