Miller began his professional career in 1991 with the rookie level Bristol Tigers, where in 13 starts, he went 2-7 with a 5.67 ERA. In 1992, still with Bristol, Miller lowered his ERA to 4.93 and was promoted to Single-A Fayetteville to begin 1993. With Fayetteville, he again lowered his ERA this time to 4.19 in 28 starts. He was promoted to Double-A Trenton in 1994. 1995 was a breakout year for Miller. Pitching for Double-A Jacksonville, the Tigers' new Double-A affiliate, he went 8-2 with a 2.72 ERA in 31 appearances. Miller's 1995 performance was good enough that he was rated the Tigers' #10 prospect for 1996 and was promoted to Triple-A Toledo. Miller went 13-6 for the Mud Hens and was a September call-up to the Tigers. He made his major league debut on September 4, 1996, against the Chicago White Sox, pitching 1⅓ innings, giving up 2 earned runs, and taking the Loss.
On December 10, 1996, Miller was traded to the Houston Astros with Brad Ausmus, José Lima, C. J. Nitkowski, and Daryle Ward for Doug Brocail, Brian Hunter, Todd Jones, and Orlando Miller. Miller spent all of 1997 with the Triple-A New Orleans Zephyrs and had a 3.30 ERA in 29 games, all but two of them starts. In 1998, he was converted to a relief pitcher and spent the whole year on the major league roster; he went 2-0 with a 3.04 ERA in 37 games. He did not fare as well in 1999, as his ERA rose by over 2 runs,
Philadelphia Phillies/Los Angeles Dodgers
He was traded to the Philadelphia Phillies during the offseason for Yorkis Pérez. Miller made the Phillies' team out of spring training, but was claimed off waivers by the Los Angeles Dodgers on May 19 and made one appearance for them before being sent to Triple-A Albuquerque. He was recalled and appeared in one more game for Dodgers on June 2 and became a free agent at the end of the season.
He became a free agent after the season and signed with the Cincinnati Reds. He was released by the Reds on September 4, 2002, without appearing in the majors.
In 2003, Miller pitched for the Toronto Blue Jays and spent the entire year in the majors. He served as a Left-handed specialist and appeared in an American League-high 79 games.
He became a free agent after the season and signed with the Tampa Bay Devil Rays where he spent the next two seasons in their bullpen recording ERAs of 3.12 and 4.06.
Houston Astros
After becoming a free agent after the 2005 season, he signed with the Astros on January 10, 2006. In the next two seasons, Miller appeared in 70 and 76 games for Houston. In 2007, Miller broke Scott Aldred's 9-year-old record for most appearances in a season without a decision. He pitched in 76 games without earning a win or taking a loss, shattering the mark Aldred had set at 48 in 1998 as a member of the Tampa Bay Devil Rays. On August 3, 2008, Miller won a decision against the Detroit Tigers, ending this modern record at 121 games.
Tampa Bay Rays
On February 6, 2008, Miller signed a one-year deal with Tampa Bay worth 1.6 million with a team option for 2009 worth 2 million. In 68 games in 2008, Miller had a 4.15 ERA. Miller's option for 2009 was declined following the 2008 season.
St. Louis Cardinals
On December 3, 2008, Miller signed a one-year incentive-laden deal worth potentially $2 million with the St. Louis Cardinals. He made his debut with the Cardinals on Opening Day, April 6, 2009. He relieved with 2 outs in the 6th inning, giving up 2 hits, being charged with a blown save, and striking out 2 batters in his 1.0 IP.
On January 30, 2012, Miller signed with the Chicago Cubs in a minor league deal, with a spring training invitation. On March 26, 2012, the Cubs released Miller.
Personal life
Miller and his wife Pari have three children, including a daughter named Grace who had two holes in her heart when she was born and a genetic disorder so rare that it doesn't have a name. Miller ran his first marathon which was the Disney Marathon in January 2009 in a time of 4 hours, 27 minutes, 27 seconds. Trever also works with the Kiwanis of Gulf Beaches and St. Petersburg local Pamela McCann in "The Trever Miller Mob 5K/1 Mile" race. February 6, 2010, will mark the race's 2nd year. All proceeds made from the run are donated to the Kiwanis of Gulf Beaches Miracle League, which is a baseball related charity associated with children with disabilities.