Zinczenko grew up in Bethlehem, Pennsylvania, and attended Liberty High School in Bethlehem. He entered the military after high school, serving in the Naval Reserve while he attended Moravian College, also in Bethlehem, for his undergraduate degree. There, he served as editor-in-chief of the student newspaper, The Comenian. He lives in New York City and Allentown, Pennsylvania.
After serving in the military, Zinczenko wrote a series of opinion pieces for The Los Angeles Times, then was hired in 1991 as assistant editor of Men's Journal, a men's magazine being launched by Rolling Stone founder Jann Wenner and editor-in-chief John Rasmus.
In 2000, Zinczenko was named editor-in-chief of Men's Health, in which he oversees the editorial content of its 38 international editions as well as the U.S. edition. Under Zinczenko's leadership, Men's Health has been nominated for nine National Magazine Awards, and has had two wins: "General Excellence" in 2010 and "Personal Service" in 2004. He also served as editorial director of Best Life, and was named editorial director of Women's Health magazine, which was spun off from Men's Health in 2005. In 2009, Advertising Age deemed Women's Health "Magazine of the Year." He served as Chairman of the 2007 American Magazine Conference and is credited with coining the phrase "magabrand," to describe magazines that expand beyond their regular formats into a variety of media and businesses. In 2008, as the editorial director of Women's Health, Zinczenko oversaw the magazine's redesign, bringing celebrities (such as LeBron James, Josh Holloway, Lance Armstrong, and Kellan Lutz) to its cover.
Zinczenko helped pass legislation in 1994 establishing the week of Father's Day as National Men's Health Week. In 2007, Zinczenko launched FitSchools, a national campaign to reinvigorate physical education programs in America's elementary schools and get children in healthy, active living. He helped provide further tools to fight childhood obesity by writing, with Matt Goulding, Eat this, Not That! For Kids, published in August 2008. The two co-wrote seven books altogether in the series: Eat This, Not That!, Eat This, Not That! For Kids, Eat This, Not That! Supermarket Survival Guide, Eat This, Not That! Best & Worst Foods in America, Eat This, Not That! Restaurant Survival Guide, Eat This, Not That! 2010, and Cook This, Not That! Kitchen Survival Guide. He is also the author of the Abs Diet series.
Zinczenko also contributes regularly to The Today Show, where according to The New York Times, he is "trotted out as a spokesman for Everyman." He has also appeared on The Oprah Winfrey Show, The Ellen DeGeneres Show, 20/20, The Biggest Loser, Rachel Ray, and Good Morning America. He has contributed op-eds for The New York Times, The Los Angeles Times, and two for USA Today. (One about the obesity epidemic and another on the decline of American men.)
In 2008, he was named Ad Week's Editor of the Year.