Gonzalez, 23, is the youngest ever winner of the award.
Gonzalez lead the Galaxy defense this year to a league-best 28 goals allowed from his center half position. In addition, the team's 0.82 goals-against average is the third-best in MLS history.
In his third MLS season, the 2009 Rookie of the Year appeared in 29 matches, and was named to his second consecutive All-Star team. He also added two goals and an assist.
Real Salt Lake's Jamison Olave, last year's Defender of the Year, finished second in the voting. He was followed by his teammate Nat Borchers, then Carlos Valdes of Philadelphia, and Todd Dunivant of the Galaxy.
The award was voted on by players, coaches and general managers, and media.
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