The album revisits the group members' youth in Ireland in the 1970s, touching on childhood memories, loves, and losses, and it pays tribute to musical inspirations of theirs such as the Ramones and the Clash.

During the five-and-a-half-year gestation period for Songs of Innocence, lead singer Bono expressed uncertainty on several occasions that U2 could remain relevant musically after the relatively lukewarm commercial performance of No Line on the Horizon.

[7][8] Planned as a sister release to No Line on the Horizon (similar to Zooropa's relationship to Achtung Baby), the project was described by Bono as "a meditative, reflective piece of work" with the theme of pilgrimage.

[21] Early that year, at Burton's invitation, Swedish singer Lykke Li travelled to Los Angeles to record backing vocals for the song "The Troubles" without U2 present.

[38] The group subsequently enlisted Ryan Tedder, Paul Epworth, Declan Gaffney, and long-time collaborator Flood to help them complete the album, hoping their opposing perspectives from Burton would benefit the songs.

[55] Thematically, Songs of Innocence revisits the group members' youth in Ireland in the 1970s, touching on childhood memories, loves, and losses, while paying tribute to their musical inspirations.

"[53] Rolling Stone deemed Songs of Innocence as having the feeling of a concept album, a notion that Bono rejected, although he did opine it was lyrically cohesive in a way the group's other records were not.

"Lucifer's Hands" is based on an instrumental piece titled "Return of the Stingray Guitar" that U2 debuted live in 2010 and performed as the opening song at each of their 32 concerts that year.

[80] Afterwards, Apple CEO Tim Cook joined them to make a surprise announcement that their 13th studio album, Songs of Innocence, had been completed and would be digitally released that day to all iTunes Store customers at no cost.

The organisation's chairman Paul Quirk said: "This vindicates our view that giving away hundreds of millions of albums simply devalues music and runs the risk of alienating the 60% of the population who are not customers of iTunes ...

"[109] Despite the poor press surrounding the release, an independent study of select iOS users by Kantar Group found that in January 2015, 23 percent of music listeners played at least one song by U2, more than any other artist for that month.

Bono described it as "an audiovisual interactive format for music that can't be pirated and will bring back album artwork in the most powerful way, where you can play with the lyrics and get behind the songs".

The artists involved in the collaboration were Robin Rhode, D*Face, Mode 2, Chloe Early, Ganzeer, Vhils, Maser, ROA, DALeast, Todd James, and Oliver Jeffers.

He suffered fractures of his shoulder blade, humerus, orbit, and pinky finger, requiring five hours of surgery at NewYork–Presbyterian Hospital/Weill Cornell Medical Center's Emergency Department.

[129] The injury forced the band to cancel a headlining appearance at KROQ Almost Acoustic Christmas,[130] as well as a week-long residency as the musical guest on The Tonight Show Starring Jimmy Fallon.

[131] The other three members of U2 kept a commitment to perform in Times Square on World AIDS Day on 1 December 2014; Chris Martin of Coldplay and Bruce Springsteen filled in as lead vocalists.

[133] To recompense the Los Angeles area for dropping out of KROQ Almost Acoustic Christmas, the band performed for 500 fans at the Roxy Theatre in Hollywood on 28 May 2015 while between shows of their arena tour.

[138] Rob Mitchum of Pitchfork criticised Songs of Innocence for "aim[ing] for a one-size-fits-all, vaguely inspirational tone, with a lean approach to details despite the press kit assertion that it's all 'very, very personal'".

[145] Greg Kot of the Chicago Tribune said U2 "sounded as impersonal as ever" and that the album was "flat and strangely complacent", while finding the more personal songs derivative of contemporary rock bands such as Imagine Dragons and Airborne Toxic Event.

[140] In a positive review, Neil McCormick of The Daily Telegraph called Songs of Innocence "fresh and cohesive... an album of big, colourful, attacking rock with fluid melodies, bright anthemic choruses and bold lyrical ideas.

"[142] In Rolling Stone, David Fricke wrote that the record was a "triumph of dynamic, focused renaissance" and "the first time U2 have told their own tales so directly, with the strengths and expression they have accumulated as songwriters and record-makers.

[62] In The New York Times, Jon Pareles said that he found the record enjoyable for its grandiose musical style and emotionally varied, nostalgic lyrics: "The songs ground philosophical musings and high-flown imagery in concrete reminiscences and events.

"[183][184] In 2016, David Sackllah of Consequence of Sound said, "U2 and Apple deserve credit for thinking ambitiously, but they overestimated the band's relevance with fans, and many felt like the automatic download constituted an invasion of privacy.

"[185] Ed Power of The Telegraph labeled the promotion "the most idiotic launch in rock history" and attributed it to two factors: the determination of Apple CEO Tim Cook to "prove himself worthy of the groovy tech guru mantle he had inherited from his far more charismatic predecessor, the late Steve Jobs", and U2's "obsess[ion] with being the biggest band in the world".

Reflecting on the iTunes release, he still thought it was a misguided idea, blaming it on U2's "fail[ure] to grasp a fundamental truth of modern consumer culture: People now care way more about their phones than any individual album".

Club, Stephen Thomas Erlewine said the concerns that the album raised with how music artists could be compensated for their work were rendered mostly obsolete as streaming services and subscription plans became ubiquitous in subsequent years.

Reflecting on the record itself, Erlewine believed that the thematic narrative U2 had intended for it was clouded by their working with too many producers and by Tedder's "glib sentimentality and glassy melodies", saying, "Somewhere underneath that processed clamor and yearning desire for relevance lies a modest, moving account of an artist attempting to come to terms with their fate by questioning their beginnings.

"[190] On the 10th anniversary of Songs of Innocence, Chris DeVille of Stereogum said that it was considered by U2 fans to be "another merely OK chapter in the band's slow slide into mediocrity" and that non-fans were "so offended at its presence on their phones that the album's quality (or lack thereof) became secondary to its status as one of the great modern PR flubs".

Upon revisiting the music, he said it was "not the turgid slog [he] remembered" but that it was ultimately an "extremely generic album, polished but insubstantial" and that it comprised a "parade of tracks that sound like soulless U2 facsimiles".

DeVille thought the record itself was always destined to be overshadowed by its iTunes distribution, resulting in it becoming "an annoyance, a meme, and a symbol of an Orwellian future in which giant corporations crowd out music of your own selection with unwanted albums that are all but impossible to delete from your device".