Constantine is also an actor, having appeared in the films A Long Hot Summer (1999), Pearls and Pigs (2003), and 8 Days to Premiere (2008), as well as the TV series Kallio (2010) and Salatut elämät (Secret Lives) (2000/2011).
Jimi was the primary songwriter in the band Technicolour and he has also composed music for Cristal Snow, Robin Packalen, Princess Avenue, and numerous Russian and Latvian artists.
He has also produced songs for Pekko Haimin and Aikakone.
He has collaborated with artists including Cheek, Uniikki, and Flowboysfamin, and contributed music to numerous film and television soundtracks.
In 2008, Jimi participated in the Tanssii tähtien kanssa (Dancing with the Stars) competition, Finland's version of the British show Strictly Come Dancing, and Suomen Pelkokerroin, the Finnish version of Fear Factor.
He also took part in the 2011 Eurovision Song Contest with his song "Party to Party", but did not qualify.
Jimi's father, Markus Hiekkanen, is an archaeologist and medieval scholar.
Constantine is a vegetarian.
He has a large octopus tattooed on his left hand, two black ribbons around his right wrist, and a smaller octopus on his chest.
He founded his own record label, JCR Constant Music Oy.