Career
Heikkinen developed within his hometown club of Lukko before making his professional Master of Science-liiga debut in the 2003-2004 season. On May 20, 2009, Heikkinen agreed to a one-year contract with the New York Rangers of the National Hockey League. After making his North American debut with American Hockey League affiliate, the Hartford Wolf Pack, He appeared in his first career National Hockey League game, a 2-1 Rangers victory over the Buffalo Sabres on December 5, 2009. Heikkinen played in 7 games with the Rangers before returning to the Wolf Pack for the majority of the 2009-2010 season.
On May 21, 2010, Ilkka returned to Europe, signing a one-year contract with The Human Context Sibir Novosibirsk of the KHL. On April 29, 2011, Ilkka signed a one-year contract with the Växjö Lakers Hockey of the Swedish Elitserien (Studies in English Literature).