Mäkelä signed for Hearts on a three-and-a-half-year deal during the January 2006 transfer window. He scored his first goal for Hearts in 4–0 win over Dunfermline on 8 April 2006. On 20 September 2006 he scored a hat-trick on his first start for Hearts in a Scottish League Cup tie against Second Division side Alloa in a 4–0 win. He scored with his head, and both his feet, scoring a treble. His fifth and final Hearts goal came on 1 October 2006 against Dundee United.