He was named the Brewers' Minor League Player of the Year in 2010 after slashing .323/.413/.442 with five home runs, 63 RBIs, and 28 stolen bases over 130 games with the Brevard County Manatees.

[1] In 2011, Komatsu first played for the Huntsville Stars and mid-year began playing for the Harrisburg Senators after he was traded from the Brewers to the Washington Nationals for Jerry Hairston, Jr.[1] Komatsu was chosen by the Cardinals in the minor league phase of the 2011 Rule 5 draft.

On April 6, 2012, Komatsu collected an infield hit in first Major League at-bat against the Milwaukee Brewers.

Playing with Triple-A Syracuse after being returned, he was placed on the disabled list with an injury on July 7 and missed the rest of the season.

Komatsu was born and raised in California and is of Japanese descent; his paternal grandmother came to the U.S. from Japan as a military bride.