His season cut short by concussion symptoms, the 33-year-old from Kelowna, B.C., made 10 appearance in MLS this year after joining the Los Angeles Galaxy in January.
"I'm extremely grateful to have played the game I love for a living," Friend said in a statement Wednesday. "I have been fortunate enough to work with some outstanding teammates, coaches and clubs who have helped shape me on and off the field over the past 10 years.
"I will always be thankful for the experiences, relationships and opportunities the game itself has given me and am honoured to finish my career as an MLS champion with the Galaxy."
The six-foot-five Friend was originally drafted by the Chicago Fire in 2003 but opted to play in Europe with stops in Norway, the Netherlands, and Germany.
He played for Moss FK and Molde FK in Norway then spent a year in the Netherlands with SC Heerenveen. Friend joined Germany's Borussia Monchengladbach for the 2007 season, leading the team with 18 goals as the team won promotion.
He spent two more years there before moving on Hertha BSC, Eintracht Frankfurt and TSV 1860 Munchen.
Friend scored two goals in 32 appearances for Canada, debuting in 2003 in a friendly against the United States.