It was written by future 10cc member Graham Gouldman, who also wrote the group's two prior singles, "For Your Love" and "Heart Full of Soul".

[3][a] When it was released 1 October 1965 in the UK, "Evil Hearted You", along with the second side, "Still I'm Sad" became a double A-side hit.

In her pop music column in Disc Weekly, Penny Valentine thought the decision to release the single as a double A-side was "madness", since "Still I'm Sad" was "super" while "Evil Hearted You" was "so dull".

[9] The biographer Martin Power writes: "Evil Hearted You" had a hint of Italian composer Ennio Morricone, with Beck's contribution taking it to a whole new level of excitement, his clattering, heavily reverbed guitar and shimmering, two-octave slide solo sounding almost ghostly.

[10]In a review for AllMusic, Richie Unterberger calls the song "one of the gloomiest hit singles in all of 1960s British rock" and adds: [It] throws in all of Gouldman's mid-'60s bag of tricks: multiple abrupt tempo changes, a haunting Middle Eastern-influenced melody extremely heavy on the minor chords, a lyric abjectly pining for a woman's love, and adroit integration of several contrasting sections.