[2] In addition to Stratovarius, Kupiainen founded the grindcore band Fist in Fetus, which released a self-produced EP in 2007.

[4] At the 2007 Tuska festival, he appeared as the one-man house band of the TV station YLE Extra.

Kupiainen has also played as a session musician, among others, on albums of Olavi Uusivirta and Milana Misic, and worked as a producer, recording engineer, and mixer, as well.

He currently plays his custom Hellcat made of Spanish cedar and arctic birch, and uses mainly ENGL, Hughes & Kettner, Mesa Boogie and TC Electronic gear.

Kupiainen was a part-owner of a recording studio named Minor Music in Helsinki, Finland, until it was merged with 5 By 5 Audio.