Klein, a former Galaxy player who later moved to the front office, was promoted to president in January. Terms of his contract extension were not disclosed.
Klein, 37, spent 12 years as an MLS player with Kansas City, Real Salt Lake and the Galaxy. He joined the Galaxy in mid-2007 and retired after the 2010 season.
"We are pleased to have a long-term agreement in place with Chris, who in a short period of time has developed into one of the most respected executives in Major League Soccer," Dan Beckerman, president and chief executive of team owner AEG, said in a statement.
The Galaxy is fourth in the MLS Western Conference but only five points behind first-place Seattle as the teams prepare to meet Saturday at StubHub Center in Carson.
The top five teams in each MLS conference at the end of the regular season qualify for the league playoffs. The Galaxy has six regular-season games remaining.
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