Zeitler was born in Waukesha, Wisconsin. He attended Wisconsin Lutheran High School in Milwaukee, Wisconsin, and played for Wisconsin Lutheran Vikings high school football team. A three-year letterwinner in football, Zeitler was honored first-team all-conference, first-team all region and second-team all-area as a junior. In his senior year, he gathered first-team all-conference, conference lineman of the year, first-team all region, and first-team all-area honors.
Regarded as a three-star recruit by Rivals.com, Zeitler was ranked the No. 39 offensive guard prospect in his class. Coincidentally, the No. 1 offensive guard in this class was Trevor Robinson, who would later play alongside Zeitler for the Cincinnati Bengals. Having numerous offers, Zeitler narrowed his decision down to Wisconsin and Michigan, before eventually picking the Badgers.
Even though "not a nifty or nimble lineman", Zeitler was described as "a solid prospect with the ability to be used in a power running offense." Projected to be a second round selection, Zeitler was ranked No. 4 among guards available in the 2012 NFL Draft by Sports Illustrated. Zeitler himself expected to be a second-rounder, having scheduled a draft-party for Day 2 of the Draft, before being surprised by the Bengals' late first-round selection. Zeitler was the eighth UW offensive lineman taken in the first round of an NFL draft since 1976, after Dennis Lick, Ray Snell, Paul Gruber, Aaron Gibson, Chris McIntosh, Joe Thomas, and Gabe Carimi.