One in a Million received general critical acclaim from music critics, who complimented its "depth" compared to that of her debut album and Aaliyah's vocal performances, with some critics calling it "smoother, more seductive, and stronger than before" and praised the "luxurious melodies and dreamy harmonies". Other critics called the album "one of the most influential R&B albums of the '90s", and it has been recognized by writers and music critics as redefining the genre coming into the late 1990s and solidifying Aaliyah's position as a key figure in R&B music. The album was ranked number 90 on Rolling Stone 's 100 greatest albums of the 1990s. It was also listed as one of 33 hip hop/R&B albums in Rolling Stone 's "Essential Recordings of the '90s".
One in a Million debuted at twenty on the Billboard 200 chart, selling 40,500 copies in its opening week; twenty-two weeks later the album peaked at eighteen, being certified Gold by RIAA. Within a few months, the album proved Aaliyah's breakthrough and a major milestone in the careers of Missy Elliott and Timbaland. It was certified double Platinum on June 16, 1997. The album was also certified Gold by the Canadian recording industry for shipments of 50,000 copies. One in a Million has sold over two million copies in the United States and 10 million copies worldwide.
The album produced six singles, "If Your Girl Only Knew", "One in a Million", "Got to Give It Up", "4 Page Letter", "Hot Like Fire", and "The One I Gave My Heart To", with the last becoming the album's highest-charting single, peaking at nine on the US Billboard Hot 100. In 2004, the album was re-released in Germany with altered artwork, and again in 2006. The disc is copy-protected, and therefore will not show up when placed in some PCs, but it will show up when inserted into a Mac, and it will play in most CD players. It included the standard 17 tracks, plus the bonus song "Come Over".
One in a Million was recorded from August 1995 to July 1996. Missy Elliott and Timbaland wrote and produced the majority of the album. Other producers included Rodney Jerkins, Jermaine Dupri, and Kay Gee. The album was executive produced by Barry Hankerson and Jomo Hankerson. 57 songs were recorded for the album, but a majority of them were cut from the final product. One of those tracks included the song, "Sugar & Spice", the first track Aaliyah did with Timbaland & Missy Elliott; however due to label disagreements with the song, it never made the final cut of the album. On October 8, 2010, a rare demo version of the song performed by 1990s R&B group, Sugah (which included notable R&B singer, Tweet) was leaked; reports have also surfaced that the track may have also been used as a sample for another R&B group, Tha' Truth, for their 1997 song, "Candy". Another track that was going to be included on the album was "I Care 4 U", but wasn't completed in time for mastering. It was later included on Aaliyah's third studio album, Aaliyah.
If Your Girl Only Knew was released as the album's lead single in August 1996, it peaked at number 11 on the US Billboard Hot 100 chart for the week ending October 19, 1996, becoming her third single to reach the top 20. It reached the top of the Billboard Hot R&B Singles chart for two weeks. "If Your Girl Only Knew" was also a hit in the UK, peaking in the top thirty of the UK Singles Chart at number 21 when it was originally released by itself. It was re-issued with "One in a Million" as a double A-side and reached a new peak position of number 15. The album's second single "One in a Million" was released December 10, 1996, the song was a top twenty hit in the UK, reaching number fifteen. "4 Page Letter" was released as the album third single on March 11, 1997. "Hot Like Fire and "The One I Gave My Heart To" were released simultaneously on September 16, 1997. Hot Like Fire charted poorly unlike "The One I Gave My Heart To" which debuted on the Billboard Hot 100 in the issue week of October 4, 1997 at number 24 and went on to peak at number 9, making it the highest-charting single from the album. In the same issue week, the song debuted on the U.S. Hot R&B/Hip-Hop Songs chart at number 18 and went on to peak at number 7. The song was certified Gold by the RIAA on October 21, 1997.
In her review for Vibe magazine, music critic Dream Hampton said that Aaliyah's "deliciously feline" voice has the same "pop appeal" as Janet Jackson's and is complemented by the producers' funky, coherent tracks. Connie Johnson of the Los Angeles Times found the album's material exceptional, including the "teasingly witchy" "If Your Girl Only Knew".Q magazine said that, with "her smooth, sweetly seductive vocal firmly to the fore, [Aaliyah] works through a set of predominantly slow and steamy swingbeat numbers, all clipped beats, luxurious melodies and dreamy harmonies".Robert Christgau, writing in The Village Voice, was less enthusiastic and cited only "Got to Give It Up" as a "choice cut", indicating "a good song on an album that isn't worth your time or money".
Since its initial reception, the album has been recognized by writers and music critics as redefining the genre coming into the late 1990s and solidifying Aaliyah's position as a key figure in R&B music. In a retrospective review, Slant Magazine said that it is "undoubtedly one of the most influential R&B albums of the '90s," and credited it for establishing "Aaliyah and the Timbo family as undeniable hip-hop forces."Allmusic viewed it as a significant improvement over her debut album with "greater variety of material" and producers, and called Aaliyah's voice "smoother, more seductive, and stronger than before". The album was ranked number 90 on Rolling Stone 's 100 greatest albums of the 90s. It was also listed as one of 33 Hip hop/R&B albums in Rolling Stone 's "Essential Recordings of the 90s".
It was an international success for the Contemporary R&B genre, with worldwide sales being 8 million as of 2008. The album debuted at number 20 on the Billboard 200 chart, selling 40,500 copies in its first week. In its 22nd week on the chart the album peaked at 18. The album was certified Gold by the RIAA on October 23, 1996; over 500,000 copies shipments. On February 5, 1997, the album was certified Platinum for shipments of over 1,000,000 units; making it, at the time, her second platinum album. On June 16, 1997, the album was certified 2× Platinum, with more than 2 million copies shipments. After Aaliyah's death, One in a Million returned to the Billboard 200, and U.S. Billboard Top R&B/Hip-Hop Albums. During this time the album also topped the Top Catalog Albums for 12 weeks.