Miller accepted an athletic scholarship to attend the University of Florida, where he played for coach Billy Donovan's Gators teams from 1998 until 2000.

As a sophomore, Miller helped the Gators avoid an upset bid by Butler in the first round of the NCAA Tournament, winning 69–68 in overtime on his floater in the lane as the buzzer sounded.

His debut game was played on October 31, 2000, in a 97 - 86 win over the Washington Wizards where he recorded 5 points, 2 rebounds and 3 steals.

On January 3, 2007, Miller made nine three-pointers in a win over the Golden State Warriors, breaking Sam Mack's Grizzlies franchise record of eight in a game set in February 1999.

[5] This made him the first NBA player to hit at least seven three-pointers in three consecutive games[6] since the Dallas Mavericks' George McCloud achieved it in 1996.

[7] Miller held the Memphis Grizzlies franchise record for most points scored in a single game, with 45 on February 21, 2007, against the Golden State Warriors.

On June 23, 2009, Miller and Randy Foye were sent to the Washington Wizards for Oleksiy Pecherov, Etan Thomas, Darius Songaila and the 5th overall pick in the 2009 NBA draft.

[12] On July 15, 2010, Miller signed a five-year, $25 million contract with the Miami Heat, reuniting with his former Gators teammate Udonis Haslem.

[13][14] Miller officially returned to the Miami Heat lineup on December 20, 2010, in a home game against the Dallas Mavericks.

Miller got his first start on January 22, 2011, due to a Dwyane Wade illness, and contributed with a season-high 32 points in a win over the Toronto Raptors.

In the next season, on January 18, 2012, Miller made six of six three-point field goals in a victory over the San Antonio Spurs to finish with 18 points in his return to the Heat, after missing several games because of an injury.

[19] He saw his minutes and his importance increase with the slightly revamped Grizzlies team led by the new coach Dave Joerger.

[23] On July 27, 2015, Miller was traded, along with Brendan Haywood and two future second-round draft picks, to the Portland Trail Blazers in exchange for cash considerations.

[29] Miller's final NBA game was played on April 12, 2017, in a 111–105 victory over the Oklahoma City Thunder where he recorded 8 rebounds and 4 assists, but no points.

[33] In July, Miller was named the boys basketball coach at Houston High School in Germantown, Tennessee.

[34] Miller and his wife, Jen, have three children: sons Mason and Mavrick, and a daughter Jaelyn.