During his career (1982–1994) he played in Finland, Italy, Switzerland, Germany, the Netherlands, and Israel for TPS, Inter Milan, Bellinzona, Bologna, Hertha BSC Berlin, Twente Enschede and Hapoel Be'er Sheva F.C.. He finished his career at a relatively young age because of a persisten ankle injury, and because concetrating more on his studies. Aaltonen studied throughout his playing career, and after retiring from football, he holds a doctorate degree in economics.
Aaltonen is best remembered for a suberb goal scored against Italian goalkeeper Walter Zenga in UEFA Cup in 1987 during a match between Turun Palloseura and Inter Milan at the San Siro stadium in Milan This goal more or less earned him a transfer to Inter shortly afterwards.
|1987-1990||F.C. Internazionale Milano, Italy|
|1988||AC Bellinzona, Switzerland|
|1989||Bologna F.C. 1909, Italy|
|1990||Hertha BSC Berlin, Germany|
|1993-1994||Hapoel Be'er Sheva F.C., Israel|