Mäkäräinen was originally a cross-country skier and focused on this until the age of twenty. She started training for the biathlon in 2003. In 2004, she made the Finnish National Team. 2005 saw Mäkäräinen compete at the Biathlon World Championships for the first time. Her best placings in the Biathlon World Championships have occurred at the 2007 World Championships in Antholz-Anterselva, where she placed eighth in the individual 15  and seventh in the mass start events. At the 2008 Biathlon World Championships in Östersund, she was 15th in the mass start. During the 2007-08 Biathlon World Cup, she made it to the podium twice, the first time when she placed second in the sprint at Pokljuka, Slovenia and third in the pursuit at Ruhpolding, Germany. During the 2008–09 Biathlon World Cup, she has steadily risen in the rankings and on she placed second during the pursuit event and third in the mass start after Iourieva and Jonsson at Antholz.