The song received favorable reviews from music critics, who deemed it "catchy" and picked as one of the best tracks on the album.

The making of the video was shown on the A New Day... Live in Las Vegas bonus DVD, called One Year...One Heart.

In October 2008, it was included on the European version of Dion's My Love: Ultimate Essential Collection greatest hits.

[1] On 15 April 2003, it was announced that after the success of "I Drove All Night," two new singles from 'One Heart' were set to impact radio.

[7] It is an upbeat, dance-pop song,[8] which draws from club-friendly house anthems,[9] about the power of love[10] and how determination and support can help a person through their problems.

[11] In the beginning, she advises to look on the bright side, with lyrics such as, "When you're down, you can start again/ Turn around anything you're in/ Love will find a place yeah".

AllMusic senior editor Stephen Thomas Erlewine wrote that "the song is sunny and catchy" and picked it as one of the best tracks on the album.

"[11] The reviewer concluded the analysis, writing: "The genial 'One Heart' is well-intentioned advice set to a paint-by-numbers, riskless dance beat".

[11] Acclaim came from Billboard: "Dion is particularly strong on the percolating title cut (a vibrant, infectious future hit helmed by Kara DioGuardi and John Shanks)".

[16] Curiously, the song also dropped the chart the following week, only returning on 7 November 2003, at number 34, its peak position.

[18] "One Heart" debuted and peaked at number 30 on the Irish Singles Chart, for the week ending 11 September 2003.

[22] On 7 June, "TeamCeline" members got an exclusive preview of the music video on her official website.