Miller played 11 seasons for the Sabres, where he went 284-146-56 with one tie when he was between the pipes. He is the Sabres leader in wins, and second in shutouts with 28. During the 2009-10 season, Miller had a 2.22 goals against average and .929 save percentage in 69 games. This was the same season he was awarded the Vezina Trophy.

In 2010, Miller helped back Team USA to a silver medal at the Vancouver Olympics, and was also named the tournament MVP.

In his sophomore year at Michigan State, Miller was the  2001 Hobey Baker Award recipient, making him only the second goaltender at the time to do so. That season he led all of college hockey with 31 wins, a goals against average at 1.32, 10 shutouts, and set an NCAA record with a .950 save percentage. Through two seasons, his 18 shutouts set another NCAA record. Not to mention, he also was named CCHA Player of the Year and Best Goaltender. In the 2001-02 season, Miller was a Hobey Baker Top 10 Finalist.

Miller officially announced his retirement on April 29, 2021 cementing his hockey legacy. On Jan. 19, 2023 the Sabres will retire his number, where No. 30 will forever be honored in the rafters of KeyBank Center.