Schillinger attended Baker High School, where he was a four-year letterman in football, and his varsity teams had an overall record of 49-1. He was a two-time all-state selection. As a senior he passed for 1,059 yards and 15 touchdowns and rushed for 650 yards and 14 touchdowns. He was a team captain for the East (along with Grizzly teammate Shawn Lebsock) in Montana's annual East-West Shrine Game. He also played in the Badlands Bowl (Montana-North Dakota All-Star Game). He also lettered four times in both basketball and track.
Schillinger played college football at Montana. During his freshman year, Schillinger was forced to redshirt because of a leg injury, but played in all 14 games in 2006 and 2007 as a backup. He started all 16 games in 2008, tying for the team lead with four interceptions and two forced fumbles to be named second-team All-Big Sky. He earned the Tony Barbour Award as the player which best exemplifies Grizzly football. He had 90 tackles and started every game as a senior, when he was named All-Big Sky, first team. Schillinger wasn't invited to the NFL Scouting Combine but did participate in the Texas vs. Nation showcase.