The song contains vocals from the Kadockadee Kwire featuring Glenn Jordan, Phillip Ingram, Jim Gilstrap, Romeo Johnson, Kevin Dorsey, and Will Wheaton.

[3] The musician subsequently released his debut studio album Straight No Chaser under the label in October 2009, with West contributing vocals on the single "Supernova".

[3] "Say You Will" was solely produced by West, who served as a songwriter alongside Jeff Bhasker, Young Jeezy, Malik Yusef, Mr Hudson, and Consequence.

[2][7] They were sampled and reprogrammed into West's Roland TR-808 drum machine at the studio, which recording engineer Anthony Kilhoffer explained was responsible for the song's "unique sounds".

[6][13][14] The notes are backed by drums, as well as vocals from monk choir the Kadockadee Kwire featuring Glenn Jordan, Phillip Ingram, Jim Gilstrap, Romeo Johnson, Kevin Dorsey, and Will Wheaton.

While naming the song as one of the album's tracks to be downloaded, The Washington Post's Chris Richards noted it contains "equally rich sonic detail" to "Street Lights".

[15] He analyzed, characterizing the song as sounding like slow riffing from "Kraftwerk and a choir of Gregorian monkbots" on the Beatles' "Eleanor Rigby" (1966) and observing how West "allows the beat to plink and plonk off into infinity" after his Auto-Tuned performance.

[15] Richards wrote that the "three gorgeous, wordless minutes" provide clarity of West "no longer clamoring for our undivided attention", instead "giving us enough space to step back and watch him take a brilliant left turn".

[20] Writing for RapReviews, Jesal 'Jay Soul' Padania named "the opening strands of the haunting 'Hey-hey-hey-hey'" on the song among the moments of 808s & Heartbreak that will remained in one's mind "for a good while".

[21] At the Chicago Sun-Times, Jim DeRogatis selected the song as one of the notable times on the album where West's formula of Auto-Tune usage "is touching and very effective".

[16] PopMatters contributor Dave Heaton stated the song "sets the mood well" for 808s & Heartbreak with its two "simple synth notes" that repeat back and forth similarly to a ping-pong game, recognizing the "strangeness" lent by them.

[23] The staff of The Observer viewed the song as sounding like R. Kelly taking on the style of Kraftwerk, labeling it "a slow jam built around a simple radioactive pulse".

[9] Cara Nash from No Ripcord viewed the song as setting the album's mood "with two synth notes beeping back and forth, desolate and bleak".

[13] Nash elaborated, saying the notes are backed by "a haunting synth choir and drums", and the song's "extended outro" serves as a reminder of West's heartbreak being "defeating and relentless".

[13] Billboard reviewer Mariel Concepcion called the subject matter of West being "unable to wrench himself away from an ex-lover" interesting, though felt that the song lacks the funness of fellow album tracks "Amazing" and "See You in My Nightmares".

[17] In a negative review for musicOMH, Adam Conner-Simons defined "Say You Will" as setting the tone for the "spaced-out synth-pop production" on 808s & Heartbreak that is simple and minimal.

[12] West performed the song for the sixth number of his February 2009 VH1 show, which was later released as his second live album VH1 Storytellers in January 2010.

[25][26] During his headlining set for the 2009 Wireless Festival at Hyde Park in London, West followed declaring the song his favorite on 808s & Heartbreak by performing a highly emotional version of it.

[29][30] The freestyle included West recounting having contacted an ex-lover late at night; he requested her to come over and was led into believing she would take up his offer, but he was ultimately denied.

[34] On November 24, 2019, West served as the offstage narrator for his debut opera Nebuchadnezzar while the song was performed by a team of singers, who sang the orchestral coda as a recurring motif.

[38][39] American trio Mobius Band released a cover version of the song on their EP Empire of Love on February 11, 2009, coinciding with Valentine's Day.

[40] The mixtape was later released to streaming services on its 10th anniversary in February 2019 with the song included; West ultimately granted his approval and received credit as a composer.

[43][45][46] They continue to sing the reinterpretation while the image gives way to a biblical quote from the New Testament Book of Mark: "In the words of Jesus Christ, 'The time is fulfilled, and the Kingdom of God is at hand, repent and believe in the gospel.