Eriksson, 27, tied for the top flight's scoring title with 14 goals for Djurgardens, finishing as a finalist for the Allsvenskan's player of the year honor.
"With Magnus, we have identified an impact player that embodies the attitude we want to represent in San Jose and the technical qualities of a leading goal-scorer in Europe," Earthquakes general manager Jesse Fioranelli said in a news release. "His ability to play multiple roles in the attack and his work ethic defensively were major factors in our decision to pursue him.
"He is in great form, having led Sweden's top league in scoring last season, and is an elite attacking player that has maintained a high level of consistency over the last five years."
Capable of playing on the flank or up top, Eriksson developed in the AIK academy before embarking on a journeyman career that has seen him play for clubs in Sweden, Belgium, China and Denmark. Eriksson, who made 11 appearances in the 2014-15 UEFA Champions League with Malmo, has one cap for Sweden and earned a call-up for the team's upcoming January camp.
Eriksson is expected to join captain Chris Wondolowski in the Earthquakes' front line, filling the void left by Marco Urena after Los Angeles FC claimed the Costa Rican forward in last week's MLS expansion draft.
San Jose finished sixth in the Western Conference last season, scoring just 39 goals — the worst haul for any team that qualified for the playoffs, and tied for the third-lowest total in MLS.
"I have had the opportunity to coach with and against Magnus for many years in Sweden," Earthquakes coach Mikael Stahre said. "I have known him since he was very young and even played a role in his decision to pursue a career in soccer instead of ice hockey. He is a very versatile player, capable of contributing from multiple positions, and will always work hard for his teammates. I'm looking forward to having him on my side once again this season."