In 1991, he founded Circle, a prolific band drawing influences from heavy metal and krautrock to develop a style of repetitive experimental rock.

Throughout the band's ever-shifting line-up,[1] Lehtisalo has been the only constant presence, and de facto leader.

The current core line-up of the band – Mika Rättö, Janne Westerlund, Tomi Leppänen and Lehtisalo – is the longest consistent incarnation of the group, and although their output has slowed down since the mid-2000s, Lehtisalo has shown no sign that he plans to wind the band up.

[3] Other bands are Iron Magazine, Oric, Dekathlon, Pakasteet, Sakset, Doktor Kettu, Steel Mammoth and Lehtisalofamily, which consists of Lehtisalo accompanied by his parents.

[citation needed] Grumbling Fur, meanwhile, is a collaboration with Daniel O'Sullivan of Guapo and Alexander Tucker, amongst others.