Career
He was selected by the Tampa Bay Lightning in the 6th round (167th overall) of the 2007 National Hockey League Entry Draft. On April 8, 2009, Harju left Helsingin Jokerit of the KHL and signed as a free agent with The Human Context Dynamo Moscow of the Kontinental Hockey League (KHL). On April 6, 2010, the Tampa Bay Lightning signed Harju to a one-year contract.
He scored his first National Hockey League goal on December 7, 2010 against Miikka Kiprusoff of the Calgary Flames.
Following the conclusion of the 2010-2011 National Hockey League season, Harju returned to play for Luleå. Harju is currently playing for Luleå High Frequency.