He is a history major at USC. His sports hero is NFL star tight end Tony Gonzalez.

He was a 1999 Super Prep All-Farwest, Prep Star All-Western, Tom Lemming All-West, Orange County Register Fab 15 third team and Las Vegas Sun Super 11 honorable mention selection as a senior at Taft High in Woodland Hills (Calif.) while playing offensive line, tight end and defensive end. Despite missing 4 games in 1999 with a dislocated shoulder, he had 6 catches for 56 yards (9.3 avg) with a TD on offense and 40 tackles, 7 sacks and 1 interception (for a TD) on defense. Current Trojans Greig Carlson, Brandon Hance and Steve Smith also prepped at Taft.

He also played basketball (earning All-L.A. City and All-League MVP honors) and baseball at Taft.
He spent 1998 at Crespi High in Encino (Calif.).

Guenther appeared as a reserve tight end in the Penn State opener (he did not catch a pass) but then suffered a herniated disk in his back and had surgery, which sidelined him for the rest of his 2000 freshman season. Because of the early injury, he was allowed to redshirt in 2000, his first year at USC.

Guenther was sidelined for most of his 2001 redshirt freshman season while recovering from a 2000 back injury. He returned late in the 2001 season, but did not see any action as a reserve tight end.

Guenther was a backup tight end as a sophomore in 2002. He even started at Kansas State. Overall in 2002 while appearing in 11 games (all but California and Notre Dame), he had 7 catches for 39 yards (5.6 avg.) with a TD. He caught 3 passes at Colorado and had a 3-yard TD reception at UCLA. He had arthroscopic surgery to remove cartilage in his left knee after the Notre Dame game (but returned to play against Iowa in the Orange Bowl).

Guenther began his 2003 junior season as a backup tight end, but after injuries sidelined starters Alex Holmes and then Dominique Byrd, Guenther emerged as the starter for the last 7 games. Overall in 2003 while appearing in all 13 games, he had 17 catches for 167 yards (9.8 avg.) with 2 TDs, plus he blocked a field goal (at California). He had a 6-yard grab at Auburn, a 7-yarder against BYU, then had 2 receptions for 24 yards at California. He added a 3-yard catch at Arizona State, a 5-yarder against Stanford and 2 grabs for 13 yards (with a 7-yard TD) at Notre Dame. He had a 7-yard catch at Washington and 2 catches for 26 yards against Washington State. His only catch at Arizona was a spectacular one-handed 20-yard TD. He made 4 receptions for 37 yards against UCLA. He sprained his left knee against Oregon State. His only catch against Michigan in the Rose Bowl was a key 19-yard third down catch to keep a fourth quarter drive alive. Following 2003 spring practice, he had surgery to repair a herniated disk in his lower back.

Guenther, USC's tallest player at 6-8 (he also plays a key role on the Trojan men's basketball team), returns as an often-used tight end as a senior in 2004 after starting there in 2003. However, it's possible he'll concentrate solely on basketball in his senior season. Because he was in competitive athletics for 8 consecutive months without a break, he was allowed to sit out 2004 spring practice.

He is recently a National Football League tight end for the Tennessee Titans