Reijo Mikkolainen began his hockey career in 1981 with Tappara Tampere and played there until 1989. With Tappara Mikkolainen won four Finnish titles (1984, 1986-88). From 1989-94 Mikkolainen played with TPS Turku and won three more Finnish titles (1990-91, 1993) with them. With his seven Finnish titles, Mikkolainen is, as of 2010, the record holder for most Finnish titles won as a player. From 1994-96 Mikkolainen played with Ilves Tampere and finished his playing career in Germany, playing one season with EC Peiting and a second season with River Rats Geretsried. Internationally Mikkolainen won silver at the 1988 Winter Olympics, bronze at the 1987 European Championships, and played with the Finnish 1989 and 1990 World Championships teams. His great-grandfather Kalle Mikkolainen won bronze in the gymnastics team all-around at the 1908 Olympics.