He played in Major League Baseball (MLB) for the Los Angeles Dodgers, Pittsburgh Pirates, Oakland Athletics, and Toronto Blue Jays.

He was originally drafted in the 21st round by the San Diego Padres in 2002, but he turned down an offer estimated at $200,000 and remained in school for another year.

He re-entered the draft the following year, and, despite having broken a bone in his left leg in a collision at first base, his stock soared and scouts projected him as a first rounder.

[4] Concern about his range caused the Dodgers to move him from shortstop to third base prior to sending him to their rookie league team, the Ogden Raptors, for the last few games of the 2003 season.

During LaRoche's second big league spring training in 2007, he noted that his last name should be spelled "La Roche" with a defined space.

On September 20, LaRoche hit his first major league home run off Colorado Rockies pitcher Matt Herges.

On March 7, 2008, while playing a spring training game against the St. Louis Cardinals, LaRoche tore the ulnar collateral ligament in the base of his right thumb.

Neither player could begin the season, and minor league rookie Blake DeWitt assumed third base duties on opening day.

[8] On May 3, after completing a ten-game rehab assignment with the Double-A Jacksonville Suns and the Triple-A Las Vegas 51s, LaRoche was reinstated from the disabled list and optioned to the 51s.

On July 31, 2008, LaRoche, along with pitcher Bryan Morris, was traded to the Pittsburgh Pirates in part of a three-team deal that sent Manny Ramirez to the Los Angeles Dodgers and Jason Bay to the Boston Red Sox.

[18] LaRoche started the season with the Triple-A Buffalo Bisons, and was called up on June 7 as a potential fill-in at third base for the injured Brett Lawrie and recently demoted Anthony Gose.

[19][20] LaRoche was designated for assignment following a 10-6 loss to the Chicago White Sox, having played just one game for the Blue Jays and going 0-4 at the plate.

Following his release, LaRoche signed with the Wichita Wingnuts of the American Association of Independent Professional Baseball and finished the 2015 season with them.

[22] On January 13, 2023, LaRoche was named the hitting coach for the Kansas City's Double-A affiliate, the Northwest Arkansas Naturals.