Jermaine Dupri and Mariah Carey co-produced their cover of the song for Dupri's debut album Life in 1472, and it was also included on Carey's 1998 compilation album #1's, later appearing on her 2001 greatest hits collection and remix compilation The Remixes. It was scheduled for release as the second single from Life in 1472 in 1998 and was meant to be given full single treatment, with the manufacturing of commercial CD singles and CD maxi-singles (among other single formats). Sony Music Entertainment retracted the commercial single at the last minute, and it was never commercially released in the United States. Some retail outlets received the commercial singles, and many of them were sold. Most stores gave them away free, or as free extras with the Life in 1472 or #1's albums. Many were still left, and Amazon.com controversially sold them for a while from January 2000.
"Sweetheart" was only given a commercial release in parts of Europe and Asia, where it garnered minor success and reached the top forty in most markets. The commercial single was originally scheduled for release in the U.S. before the eligibility rules for the Billboard Hot 100 chart were changed to allow album cuts to chart. Following the change of rules for the Hot 100, the rules for the Bubbling Under Hot 100 Singles chart were changed as well, to allow airplay-only songs that were bubbling under, or had not yet entered the Hot 100, to chart there. "Sweetheart" began to receive radio and music video airplay in early September 1998, and in the first week of the rule change, when the song's run as a promotional single was ending, it entered the Bubbling Under Hot 100 Singles chart at 25 and remained on the chart for one week. Another example of a song that peaked low on the chart near the end of its run due to the rule change was Natalie Imbruglia's "Torn", which had a long run at number one on the Billboard Hot 100 Airplay chart.
The single's video, directed by Hype Williams, shows Dupri and Carey in various locations ranging from a modern Spanish art museum (the Guggenheim Museum Bilbao) to a secluded beach and an exclusive nightclub. The song's theme of having a "sweetheart" runs throughout the video. Carey and Dupri re-recorded their vocals for a remix of the song, known as "Sweetheart" (The Story), which features more raps by Dupri and fewer vocals by Carey. Lil Jon, Mark Picchiotti, and Eddie Arroyo also created remixes of the song.
Allmusic editor Stephen Thomas Erlewine highlighted this track. When the same critic reviewed the same song in Mariah's Number 1's he called it fine but not particularly memorable. Jon Dolan od Citypage music wrote that Dupri is romancing pop queen Mariah Carey in the squeaky clean, radio-gimme "Sweetheart." Entertainment Weekly's David Browne wrote: "Even Carey contributes, perhaps unwittingly (...) On the mild electro-funk of "Sweetheart," she turns herself into a subservient Barbie, cooing about her need for a "storybook romance." Kris Ex of Vibe wrote that Mariah Carey-belted "Sweetheart" updates Rainy Davis's '86 hit of the same name but "it's jams are swollen with riverting bass runs."