Reus left Borussia Dortmund at the end of last season after 12 years with the Bundesliga club, and joins the American side as a free agent. His final game for the German club was in their Champions League final defeat to Real Madrid in June.
"For Marco, a two-time Bundesliga Footballer of the Year, to join the Galaxy after playing his entire career in Germany is a testament to the project we are continuing to build at the club," LA Galaxy General Manager Will Kuntz said.
Reus scored 170 goals in 429 games for Dortmund and captained the side for five years until 2023, winning two German Cups with them. He also scored 15 times for Germany in 48 appearances.
"He is a proven winner and leader whose talent and vision for the game will integrate seamlessly into the group as we prepare for the restart of the league and the run into the playoffs," Galaxy coach Greg Vanney said.
LA Galaxy are top of the Western Conference and their next game is at home to Atlanta United on August 25th. The deal means Reus will be at the club until the end of the 2026 season.