He is currently playing for Salavat Yulaev Ufa of the Kontinental Hockey League (KHL). Hartikainen was drafted 163rd overall by the Edmonton Oilers in the 2008 National Hockey League Entry Draft. Hartikainen played three seasons in the Master of Science-liiga for KalPa before joining the Oiler American Hockey League affiliate, the Oklahoma City Barons, for the 2010-2011 AHL season.
2006-2007: In nine games with the KalPa U18 squad, the winger tallied five goals and 11 points, adding another three points (2g+1a) in 11 games with the U20 team
2007-2008: Hartikainen appeared with three different KalPa squads this season. In seven games with the U18 squad, he netted a career-high nine goals and 15 points, adding another 17 points (10g+7a) in 37 games with the U20 KalPa team
He failed to register any points in his lone game with the KalPa Master of Science-Liiga team H also suited up for six games with the Finland National U18 team, netting two goals and three points at the WJC-18.
2008-2009: The Finnish winger continued his hockey career within the KalPa system, appearing in his first full season with the teams Master of Science-Liiga squad.
He also potted another nine points (3g+6a) at the WJC with Team Finland
Hartikainen was named the AHL"s rookie of the month in January 2011. On March 14, 2011, Hartikainen was recalled from the Oklahoma City Barons by the Oilers. On March 17, 2011, Hartikainen made his National Hockey League debut in a 3-1 loss against the Phoenix Coyotes, he recorded an assist on a third period power play goal by Magnus Paajarvi.
On March 26, Hartikainen scored his first National Hockey League goal against Calgary netminder Miikka Kiprusoff in a 5-4 Shootout loss against the Calgary Flames.
On June 10, 2013, after three years of attempting to make it on the Oilers full-time roster, Hartikainen left the Oilers as he signed a contract in the Russian KHL with Savalat Yulayev. On January 31, 2014, Hartikainen"s National Hockey League rights were traded by the Oilers to the Toronto Maple Leafs in exchange for Mark Fraser.