The symbol features a combination of a heart and a pentagram, the heartagram is meant to represent the juxtaposition of "the soft and the hard, the male and the female, the yin and the yang" according to Valo.

Musically the heart is also meant to represent the softer side of the band, while the pentagram symbolizes their heavier influences. This juxtaposition was also prevalent in the band's album titles. On their first album, HIM used a heart with "666" inside it as their logo, which Valo later felt was "a bit boring". The heartagram was first predominantly used on the cover of HIM's 2003 album Love Metal, and has since appeared on numerous releases from the band.

Valo has later stated that the heartagram "is probably the best thing I've ever come-up with", and that it's "worth a lot more than money" and is "bigger than our band". The heartagram has also made several appearances on TV, including Charmed, LA Ink, Viva La Bam, and Criminal Minds.