Career
When he and Heinonen started at Suutarila high school in the early 1990s, they met Pauli Rantasalmi and later Janne Heiskanen. Ylönen initiated the project of The Rasmus (then called just "Rasmus") in 1994, along with Eero Heinonen (bass) Pauli Rantasalmi (guitar), and Jarno Lahti (drums), with Lahti subsequently being replaced by Heiskanan. Ylönen became the lead singer, composer and songwriter of the band. He quit school because the band took too much of his time.
In 2004, Ylönen recorded a song together with Apocalyptica and HIM's singer Ville Valo, named "Bittersweet".
Most recently, Ylönen announced a solo album scheduled for release in March 2011 with the first single Heavy being out in February.