[1] Hillenmeyer attended high school at Montgomery Bell Academy and played college football at Vanderbilt University.

Hillenmeyer was a four-year letterwinner at Vanderbilt (1999–2002) where he saw action in 45 games, starting the final 23 (every contest from 2000 to 2002) and tallying 249 tackles (165 solos) and 6.5 sacks.

[6] In announcing the defensive starters for a 2006 Monday Night Football game against the St. Louis Rams, Bears teammate Alex Brown nicknamed the linebacker "Triple H Hunter Hillenmeyer".

[7] On September 14, 2010, Hillenmeyer was placed on the Bears injured reserve list after sustaining a severe concussion in the team's season opener against the Detroit Lions.

Hillenmeyer pursued a part-time MBA program at the Kellogg School of Management at Northwestern University in Evanston, Illinois.

[9] In 2013, Hillenmeyer founded a company called OverDog, which allows fans to compete against pro athletes in video games over a mobile app.