The artists wrote the song alongside Phillip Lawrence and producer Ramon "REO" Owen of the Soundkillers, with co-production from the Smeezingtons.

Music critics gave "Mirror" positive reviews praising it for Mars's smooth, epic hook and Wayne's introspective verses.

The hip-hop and rap ballad has been compared in its composition to "Lighters" (2011) by Bad Meets Evil featuring Mars and lyrically to Wayne's single "How to Love" (2011) from the same album.

"Mirror" debuted at number 16 on the Billboard Hot 100 and peaked in the top 15 of Denmark, Netherlands, Switzerland, and Belgium (Flanders).

Antoine Fuqua directed the accompanying music video, filmed in November 2011, with visual effects created by GloriaFX.

The video ends with a scene showing a painting of Wayne, toned in red, crucified on a giant treble clef holding a mic in his left hand.

[2] On November 1, 2011, the single was re-released in the same format and to rhythmic contemporary stations by Cash Money and Universal Republic Records.

Michael "Banger" Cadahia and his assistant Edward "Jewfro" Lidow recorded it at CMR South Studios in Miami, Florida.

Owen initially wanted the track to be a part of West's My Beautiful Dark Twisted Fantasy (2010); he "settle[d]" for it being included on Tha Carter IV.

Owen claimed he alone produced the track with the Smeezingtons as co-writers; however, the CD's liner notes also credit the team as co-producers.

[5][14][15] Rap-Up noticed the structure of "Mirror" resembles the one of "Lighters" (2011) by Bad Meets Evil, which also features Bruno Mars.

[15] In the track, Mars shows his emo-angst by singing: "Through my rise and fall/ You've been my only friend" and Wayne gets "reflective" on his verses "Looking at me now I can see my past/Damn, I look just like my f—king dad/Light it up, that's smoke in mirrors/I even look good in the broken mirror.

[18] Various publications affirmed that Lil Wayne took inspiration from Michael Jackson in one of his verses: "And no message any clearer, so I'm starting with the "Man in the Mirror" (1987).

[15][17] Idolator's Becky Bain found similarities between Wayne's single "How to Love" (2011) from the same album for its "introspective, sad and sweet" lyrics.

"[5] Billboard's Joe DeAndrea commented that the track was not only among Lil Wayne's best material, and found the vocals on the hook provided by Mars are quite "smooth".

[41][20] The video begins with a shirtless Wayne standing in a room, while a camera shows various close-ups of his intricate tattoos.

complimented Wayne's final painting and called the rapper's video a "bizarre art world exploration".

[12] Chris Coplan of Consequence of Sound said that the final scene made the "Mona Lisa look like Dogs Playing Poker.