The song was released just twelve hours prior to the release of
Assume Form through
Polydor Records. It premiered on
Zane Lowe's
Beats 1 show, where Lowe reportedly played the song three times over and said "James Blake, you’ve done it again." "Mile High" was met with positive reviews from
music critics, most praising the three artists' chemistry.
Consequence of Sound deemed it the best track of the week, writing that it "proves that Scott can fit in on more than just his signature bangers, with an almost comforting delivery that’s more inviting than assertive."
Stereogum gave it the same accolade, noting that "There’s a stuttering sample of something — a flute maybe? — that echoes like a birdcall through a rainforest. It’s lovely." Robert Marshall of
Hypebeast hailed the track as " perfect marriage of the trio’s distinct sounds, while also proving Blake’s sonic progression." Ben Devlin of
MusicOMH echoed these views, writing that "it shows remarkable chemistry." ==Music video==