"I am honored to be the head coach for the most decorated club in Major League Soccer," Schelotto said in a statement.
"This is a tremendous opportunity for me and I am excited to get to work. The LA Galaxy have long been the standard in MLS and I am ready to push the club to new heights."
He replaces Dominic Kinnear, who took over as interim head coach when Sigi Schmid resigned in September. Schmid died on Christmas Day.
"After a comprehensive search, domestically and internationally, we believe Guillermo will be a landmark signing for this club," said LA Galaxy general manager Dennis te Kloese.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"Guillermo is a proven winner who has experience coaching, playing and winning for big clubs. It is our hope that Guillermo’s managing style and familiarity with MLS will bring trophies and championships to LA Galaxy fans and the city of Los Angeles."
Schelotto, 45, spent the majority of his 16-year playing career at Boca, winning three Copa Libertadores titles and scoring 86 goals.
He made 10 national team appearances for Argentina.
(Reporting by Andrew Both in Cary, North Carolina; Editing by Frank Pingue)
