Miller is an eight-time Pro Bowl selection, receiving first-team All-Pro honors three times and second-team All-Pro honors four times. As of , he has the most career sacks of any active player and the most career sacks in Broncos history at In his junior year, he recorded 37 tackles, 14 tackles for loss, 7 sacks, and 12 quarterback hurries.
In track and field , Miller competed in events such as the m hurdles personal record PR of Considered a four-star recruit by Rivals. As a freshman at defensive end in , he was named Freshman All- Big 12 by The Sporting News after posting 22 tackles, including 10 solo stops.
He recorded two sacks, four tackles for loss, and a forced fumble. He weighed pounds during his freshman year. In spring , newly hired head coach Mike Sherman was discouraged by Miller's habits of skipping class and failing to produce during practice. Sherman decided to suspend Miller for that spring. Disappointed, Miller considered transferring, but upon his father's insistence, stayed.
Miller then adopted a more serious attitude. As a sophomore in , Miller played at weakside linebacker under Joe Kines 's 4—3 defense. He saw action in all 12 games, making 44 tackles, including 25 solo stops, and leading the team with 3. He made 7. His role was more confined to pass coverage, as opposed to rushing the quarterback, thus he was not able to showcase his pass-rushing abilities.
In his final seven Big 12 games, he compiled just eight tackles. He enjoyed a breakout season for the Aggies, leading the nation in sacks with 17 and ranking fourth in the nation with 21 tackles for loss.
