Eero Heinonen is the bassist for the Finnish band, The Rasmus, which first formed in 1994 while band members Lauri Ylonen, Pauli Rantasalmi, Janne Heiskanen, and he were still in high school. Heinonen was born in 1979 in Helsinki, Finland.

The Rasmus released their first album when the band members were only sixteen years old and the band was known only as Rasmus. The album was titled Peep and was released by Warner Music Finland, where it promptly went gold. After their initial success they followed up with two more albums, and earned even more support and recognition when they opened up for bands like the Red Hot Chili Peppers and Garbage when the groups would tour Finland.

However, the band changed its name to The Rasmus in 2000 after they took on Aki Hakala to replace the drummer, Janne Heiskanen. Since then the band has been experiencing a large increase in their fan base as they have hit the top of the charts in Britain, Australia, Austria, Switzerland, Germany, and New Zealand. In 2006 the band also released their album, Hide from the Sun, in the United States through their new U.S. label, DRT Entertainment. This latest album should only further serve to allow more and more people across the globe to be able to hear their music, exponentially increasing their fan base.

Despite the success they experienced, Eero found himself having to seek immediate medical attention after the band made an appearance at the Reading Festival in 2004. This was because the band suddenly found themselves being pelted with plastic bottles and mud by members of the audience.

Eero has taken the band's success in stride and is the only member to currently be married. He is also the father to two young children and is capable of playing the violin. Eero enjoys taking time to participate in side projects and for years he played in a band known as the Korpi Ensemble. However, since 2004, Eero has been participating in a new band called Hay and Stone. Eero is both the bassist and the lead singer for Hay and Stone.