Drenttel was the president and a partner of Drenttel Doyle Partners, a design company that worked in a wide range of areas, including corporate design, new product development, package design, collateral materials and advertising, marketing consultation, architectural and environmental graphics, and editorial design. Drenttel ran the firm, along with principals Stephen Doyle and Thomas Kluepfel. Drenttel Doyle Partners was first located at 77 Irving Place and then at 1123 Broadway, both in New York City. Among its accomplishments, Drenttel Doyle Partners made a significant impact on magazine design with its design of Spy Magazine and The New Republic in 1986; designed the identity for the World Financial Center in 1988; launched retail cash machines for Citibank in 1992; repositioned the Cooper-Hewitt Museum as the National Design Museum in 1995; designed Martha Stewart products into K-Mart in 1997; and created graphic identity programs for three national educational institutions: Teach for America in 1994, Edison Project in 1994 and Princeton University in 1996. Additional selected clients over a 12-year period included Brooklyn Academy of Music, Champion Paper, Elektra Records, Farrar Straus & Giroux, HarperCollins, Hewitt Associates, Inc. Magazine, Metropolitan Transportation Authority, Museum of Modern Art, National Audubon Society, The New Republic, Olympia & York, Springs Industries, St. Vincent's Hospital, and Wildlife Conservation Society. Winterhouse Studio (1997-2012) In 1997, Drenttel started Winterhouse with his partner, Jessica Helfand. Winterhouse is a graphic design consultancy studio focused on publishing and online media, cultural and educational institutions, and design and social innovation that first operated from 214 Sullivan Street, New York City. In June 1998, the studio moved to Falls Village, Connecticut. From its rural location in northwest Connecticut, Drenttel sought to create a new kind of design practice that innovated how designers participate in large social issues and programs, both nationally and internationally. Winterhouse Studio initially focused on publishing and editorial development; new media; and cultural, educational and literary institutions. The studio designed Netscape tools, browser and homepage in 1998-1999, University Business in 1998, New England Journal of Medicine in 2000, Legal Affairs, Norman Rockwell Museum in 2002, Berkshire Taconic Community Foundation in 2003, New York University School of Journalism and The Paris Review in 2004, Yale Law Journal and The Poetry Foundation in 2005, The New Yorker in 2007, Archives of American Art Journal, Yale Environment 360 and Teach For All in 2008, and Harvard Law Review in 2010. Additional clients included Yale University