Davis was inspired by the political and racial subtext of Johnson's saga as well as the hard rock and funk sounds of his own era, leading a rock-inspired line-up of musicians in the studio: guitarists John McLaughlin and Sonny Sharrock, keyboardists Herbie Hancock and Chick Corea, saxophonist Steve Grossman, bass clarinetist Bennie Maupin, electric bassist Michael Henderson, and drummers Jack DeJohnette and Billy Cobham.

[4] The music recorded for Jack Johnson reflected Davis' interest in the eclectic jazz fusion of the time while foreshadowing the hard-edged funk that would fascinate him in the next few years.

[5] Having wanted to put together what he called "the greatest rock and roll band you have ever heard",[6] Davis played with a line-up featuring guitarists John McLaughlin and Sonny Sharrock, keyboardists Herbie Hancock and Chick Corea, saxophonist Steve Grossman, bass clarinetist Bennie Maupin, and drummers Jack DeJohnette and Billy Cobham.

"[11] Liner notes accompanying a later release of the album provide a description of the music: Michael Henderson launches into an enormous boogie groove with Billy Cobham and John McLaughlin.

[12]According to The Guardian's Tim Cumming, Jack Johnson abandoned jazz and the broad textures of Bitches Brew in favor of a concerted take on hard rock and funk, inspired as well by politics, the black power movement, and boxing.

[20] Reviewing the album in June 1971 for The Village Voice, rock critic Robert Christgau gave Jack Johnson an A-plus and said it is his favorite recording from Davis since Milestones (1958) and Kind of Blue (1959).

Viewing Jack Johnson as a "letdown after the unflawed triumph" of Bitches Brew, Feather was particularly dismayed by Davis for aligning himself with "the thumping, clinking, whomping battering ram that passes for a rhythm section" on the album.

[32] In The Penguin Guide to Jazz (2006), Richard Cook says Jack Johnson "stands at the head of what was to be Miles Davis's most difficult decade, artistically and personally",[30] while Tom Hull names it one of the "true highlights" of the trumpeter's electric period and among his best albums.

He also calls it "the purest electric jazz record ever made because of the feeling of spontaneity and freedom it evokes in the listener, for the stellar and inspiring solos by McLaughlin and Davis that blur all edges between the two musics, and for the tireless perfection of the studio assemblage by Miles and producer Macero".

[22] John Fordham from The Guardian observes a transition in Davis's playing from a "whispering electric sound to some of the most trenchantly responsive straight-horn improvising he ever put on disc".

According to Fordham: Considering that it began as a jam between three bored Miles Davis sidemen, and that the eventual 1971 release was stitched together from a variety of takes, it's a miracle that this album turned out to be one of the most remarkable jazz-rock discs of the era.

The following lineup, recorded at Columbia Studios, February 18, 1970, was uncredited on the original LP and are only heard on a section of "Yesternow" (from 14:00 to 23:55) playing a composition called "Willie Nelson":