Lepistö played professional hockey for Jokerit in the Finnish SM-liiga. In 2003–04, his first season, Lepistö had 3 goals and 7 points in 53 games, followed by one assist in eight playoff games for Jokerit. He also played for Finland in the 2004 World Junior Ice Hockey Championships, scoring four goals and eight points in seven games. Lepistö saw his offensive numbers rise in 2004–05, as he had 7 goals and 25 points in 55 games. Lepistö also had a solid playoff performance for Jokerit, scoring 1 goal and 8 points in 12 games.