Mars' writing and production team, the Smeezingtons, composed the whole record and worked with several past collaborators, Jeff Bhasker and Supa Dups, while enlisting new producers, such as Mark Ronson and Emile Haynie, and no guest vocalists.

The album was initially planned to be more "energetic" than his previous work, but ended up presenting a wide range of styles such as R&B, pop, reggae, rock, disco, funk and soul music.

[1] Due to the numerous television shows and worldwide performances provided by Mars, he acknowledged that his second studio album needed to display his "raucously" dynamic appearances on stage.

[2] Because he had been a composer of pop and radio-friendly songs for a long time, it ultimately influenced the style of his debut; however, he didn't have the chance to craft the "sounds and sonics" he wanted to.

[2] As a result, Mars hoped to "let loose" and discuss darker, more risqué subject matter, while drawing on the "danger" embraced by pop artists such as Michael Jackson and Prince.

[8] Previously, Benny Blanco, Emile Haynie, Diplo, Supa Dups, as well as Mars's production team the Smeezingtons, have been confirmed to have worked on the album.

[3][9] The first song written for Unorthodox Jukebox was "Gorilla", which "set the tone for the entire project"; Mars explained in an interview granted to MTV News that it became its mascot hence the reason it ended up as the album cover.

[6] While being interviewed for his Billboard Artist of the Year cover story, Mars complimented Ronson and Bhasker by explaining that "it's not about what's hot on the radio or the fastest way to make a buck, these guys are fearless, doing the music they want to do".

[25] The song "When I Was Your Man" is a pop piano ballad and shows traditional notions of romance, a pre-fame heartbreak as Mars regrets letting his woman get away.

[15] Andy Gill of The Independent called it a "McCartney-esque piano ballad",[31] while Jason Lipshut of Billboard wrote that "it will make for a killer lighters-in-the-air moment in concert.

[20][2] It received positive commentary from music critics, who praised its reggae, rock and funky beat, but also its lyrics for talking about passion in a "tidy and impeccable" way.

[49] It received generally favorable reviews from critics, who praised it for "[echoing] the peppy sound of such pop/R&B hit-makers of the 1970s and 1980s as the Sylvers, Heatwave, DeBarge and Kool & the Gang.

"[50] To promote the single, Mars performed on various occasions, including a "little extra Michael Jackson-esque, circa Off the Wall and Thriller" show at the 2013 Billboard Music Awards.

[62] On October 15, 2012, the album was made available for pre-order worldwide via Mars's official site, offering different options to purchase including an immediate MP3 download of "Locked Out of Heaven", the standard CD or digital release, the deluxe bundle (which included the record's physical issue, a T-shirt, and an ultimate bundle packaged similarly to the deluxe edition that featured an autographed screen print poster limited for the first 300 orders), and a key necklace for the single.

[66] Mars performed "Locked Out of Heaven" and "Young Girls" for the first time on Saturday Night Live on October 20, 2012, while receiving positive reaction from critics and the audience.

[12] Rolling Stone magazine's Jody Rosen awarded Unorthodox Jukebox four out of five stars, writing that, "The result is a record that makes the competition sound sad and idea-starved by comparison".

[81] Dan Hyman from Spin granted the record an 8/10 rating, pointing out that "the bulk of Unorthodox Jukebox benefits from presenting [the singer] as he truly imagines himself: a big belter with an ear for pop hooks, sure, but one unafraid to dive into murkier waters."

[32] BBC Music's Matthew Horton said that the captivating album showcases the singer's knack for songs with chart potential, while noting the incorporation of rock and soul.

[13] Sarah Rodman from The Boston Globe felt Mars "is trying to rough up his image a bit" as it is undeniable in "his strong, if sometimes oddly lyrically aggressive, second album".

[35] Ryan Reed, writing in Paste, gave Unorthodox Jukebox a 7/10 rating, confessing that "Mars still plays the sweetheart card well, but he's proven himself way more interesting as a badass".

[36] In a mixed review, Caroline Sullivan from The Guardian, Kitty Empire from The Observer, and Andrew Chan from Slant Magazine all rated Unorthodox Jukebox three out of five stars.

[22] Empire felt that Mars still lacks a characteristic style, observing "a little more hooliganism" than on his first album and feeling that, "despite its title, [it] deserves your grudging respect" while noting the incorporation of reggae on the record.

[23] Closing the review, Chan called it "not an unqualified triumph, Unorthodox Jukebox is a step forward" and completed his idea saying that the singer "minor limitation" and "the key to his appeal" on a record that is "a reasonably listenable exercise in genre fetishization.

"[24] Andy Gill of The Independent felt that the singer is a "talented chap", but resorts to imitations of past recording artists on the album, "whose title all but gives the game away".

[31] Fiona Shepherd of The Scotsman wrote that Unorthodox Jukebox is "a safe mixtape, especially compared to what Mars can pull off live with his terrific soul revue band".

Club's Evan Rytlewsk gave Unorthodox Jukebox a C+, commenting that Mars is "an undeniable talent, desperately searching for an identity to claim as his own", though praising the tracks "Locked Out of Heaven", "Natalie", "Treasure" and "Show Me".

[21] In September 2024, Billboard's Kyle Dines affirmed that Unorthodox Jukebox "cemented Mars's status as one of the most commercially dependable male pop stars of his time.

[100] In the week of February 5, 2014, following Mars's presence at the 56th Grammy Awards and performance at the Super Bowl XLVIII halftime show, sales for the album increased by 180%, rebounding Unorthodox Jukebox back in the top ten.

[102][103] The album has been certified six times platinum by the Recording Industry Association of America (RIAA) for sales and streaming figures equivalent to six million copies.

[110][111] It first brought total sales to over 100,000 copies in the United Kingdom, thus earning a gold certification, but was later certified three times platinum by the British Phonographic Industry (BPI).