The Southern California native played three seasons in LA, helping the club win back-to-back MLS titles in 2011 and 2012.
“Hector is an exciting young player and we are pleased to welcome him to our club,” Crew sporting director and head Coach Gregg Berhalter said in a news release. "He is a player that possesses several strong attacking attributes and will help our squad immediately."
Jimenez, 25, was drafted by LA in the second round of the 2011 SuperDraft. In three seasons with the team, the midfielder has made 43 appearances and has scored four goals and added six assists, winning MLS Cup in 2011 and 2012.
The Galaxy will now enter the MLS SuperDraft without a first round selection for the first time since 2007 and just the third time in club history.