Hietanen began in youth in OTP Oulu. About the FC Jazz Pori (1996-1997) and the Swedish IFK Norrköping (1997-1999), he came in 1999 to Vaasa PS. For the club he played in the highest Finnish league, the First Division.
In January 2002, the defender moved for around 130,000 € in Turkey to Denizlispor, where he was one and a half years active. Here he played in the UEFA Cup. 2003 he moved to Spain to second division UD Las Palmas, with whom he but only the 20th place in the Segunda División occupied and thus in the Segunda División B descent. In January 2005, he joined the Norwegian Tippeligaen to Tromsø IL, before he returned in the summer to Spain and signed in Córdoba CF. With the club he was in sixth Segunda División B. 2007 and 2008 Hietanen played back in the First Division. This time for the AC Oulu from his birthplace. Hietanen played 25 games and was able to achieve five goals. In 2008 he moved again his club and went to the French club Troyes AC, for which he ran aground six times in Ligue 2 ( second French league). For the season 2008/ 09 Hietanen went to the Belgian club KSV Roeselare, which he left in 2010. Since (as of January 2011) he again plays for AC Oulu.
Hietanen also played 16 matches (as of October 2010) for Finland, the first in 2000.