Johansson is son of Swedish jazz pianist Jan Johansson and brother of Ex-HammerFall drummer Anders Johansson. He is highly influenced by classic rock keyboardists like Don Airey, Eddie Jobson and Jon Lord. In 1982, the classically trained Johansson left the jazz fusion band Slem and joined the Swedish metal band Silver Mountain, which also included Anders. In 1983 he left Sweden for California and joined guitarist Yngwie Malmsteen as a member of his band, Rising Force. Numerous records and world tours ensued and he stayed with Yngwie until 1989. Johansson also played with the band Dio between 1989 and 1990. Like Anders, he began an ongoing collaboration with Jonas Hellborg in 1989 which has resulted in several progressive and avant-garde recordings, including "Dissident", "Unseen Rain" (an acoustic piano trio record with Ginger Baker on drums) and the hard core progressive fusion record, "E".