Columbia Records released the song, the album's fourth single, to mainstream radio in the United States on January 20, 2009, and to international markets from February 20.

Inspired by Ray LaMontagne's 2004 song "Shelter", "Halo" was written by Ryan Tedder and Evan Bogart, with the former producing it alongside Beyoncé, who handled the vocal production.

"Halo" received positive reviews from music critics, who made comparisons with Lewis's 2007 song "Bleeding Love", also written by Tedder.

An alternative music video, which shows Ealy's character being chased by police officers through a forest at night, was posted on the Internet in May 2010.

Kidd suggested they create a song in the style of LaMontagne's "Shelter" for Beyoncé and her husband Jay-Z, and proposed the title "Halo" after hearing Tedder play "angelic" chords.

According to Simon Cowell, owner of the music production company Syco Entertainment, Bogart and Tedder intended "Halo" for his client, singer Leona Lewis, who could not record the song because of her tight schedule.

[2] David Balls, editor of the British media website Digital Spy, asked Tedder during an interview whether "Halo" had initially been written for Lewis.

Mark "Spike" Stent mixed the track with assistance from Matt Green, and Jim Caruana recorded Beyoncé's vocals; both these tasks were done at Roc the Mic Studios.

[25] Backed by a piano, claps and step stomps that set a spiritualized atmosphere,[13][16] Beyoncé opens the song with the lines: "Remember those walls I built?

[8][17] Beyoncé then echoes the word "halo" in the chorus;[10] the third and final one is preceded by a 1980s drum breakdown, and is complemented by sweeping strings and percussion.

[27] "Halo" was taken from a different disc of I Am... Sasha Fierce to "Diva"; the intention was to demonstrate the concept that Beyoncé has conflicting personalities—the central theme of the album.

[33] On February 20, 2009, "Halo" was released as a two-track digital download, including a remix of "Single Ladies (Put a Ring on It)" in Australia[34] and New Zealand.

[47] She eventually realized their resemblance when she listened to both recordings closely; the similarities are most notable in the backing tracks, which in both cases feature a melancholy piano, loud drums, and handclaps.

"[50] Clarkson later told James Montgomery of MTV News that it was unfortunate "Already Gone" and "Halo" sound so similar, but noted that at least they have different vocal melodies.

[11] Michael Slezak of Entertainment Weekly described "Halo" as "an absolutely glorious and perfectly produced track", which had the potential to be as commercially successful as "Crazy in Love" (2003) and "Irreplaceable" (2007).

Online wrote that the song could be included on a romantic mixtape,[52] and James Montgomery of MTV News noted that the "tear-jerking power" of "Halo" reveals "sides of Beyoncé we never knew existed".

[76] The song spent 33 non-consecutive weeks on the chart, and was certified platinum by the Recording Industry Association of New Zealand (RIANZ), representing sales of 15,000 copies.

[99] An alternative video surfaced online in late May 2010, explaining why Beyoncé's character was remembering her love interest in the original version.

[96][100] It begins with a view of the night sky and many trees, as Beyoncé drives a car and Ealy's character is chased by the police through a forest.

[101] Brennan Williams of Entertainment Newswire wrote that Beyoncé's "breathtaking performance" showed why she received the 2009 Outstanding Female Artist award.

During some concerts, an image of Jackson was shown on the main screen and she changed the lyrics to "Michael I can see your halo / I pray your music won't fade away".

[124] Following the death of Whitney Houston earlier that year, Beyoncé performed a tribute during her Live revue in May 2012, at the Revel resort in Atlantic City, New Jersey.

[126] Maura Johnston of The Village Voice praised the performance noting that "the most basically structured song [...] could be turned into something glorious with the right singer".

[128] "Halo" was blended with the Katrina and the Waves' 1985 song "Walking on Sunshine", in the "Vitamin D" episode (2009) of the Fox Broadcasting Company television show Glee.

[138] Elementary school group PS22 Chorus covered "Halo" and "Single Ladies" during the 2009 Billboard Women in Music luncheon held at The Pierre in New York City.

[139] At the 2009 MTV Europe Music Awards, American singer Katy Perry performed a mash-up of "Halo" and the other Best Song nominees.

[148][151] Simon Vozick-Levinson of Entertainment Weekly commented that their version "stays fairly close to the original, except with Elephant Man growling instead of Beyoncé belting the verses".

[152] A 2012 cover by singer-songwriter LP was described by MTV as "[finding] the perfect balance between making it her own and preserving the integrity of the original melody".

[156] Indian singer Sunidhi Chauhan covered the ballad during a concert at the Royal Albert Hall in London in late September 2013.

[157] In 2013 Ane Brun, accompanied by Linnea Olsson on cello and backing vocals, released a "personal and stripped-down" version of "Halo" on her album Rarities.