Bieber performed the song several times, including on Saturday Night Live, and the ninth season of American Idol.

A few days before the release of the single, Bieber posted an acoustic version of the song to his YouTube with his guitarist Dan Kanter, similar to the way he did with "Favorite Girl".

"[6] The song is predominantly upbeat, featuring Bieber's R&B vocals over a backdrop containing a dance infused beat, full of keyboard and "disco string" synths.

[7] The song is played at a tempo of 130 BPM and is composed in the key of E♭ major with Bieber's vocal range spanning from the low-note of G3 to the high-note of C5.

[8][9] According to Jody Rosen of Rolling Stone, the song "blends winks at Fifties doo-wop with hip-hop chants", comparing the style and the lyrics "My first love broke my heart for the first time/And I was like/Baby, baby, baby, ooooh/I thought you'd always be mine" to fifties ballads like "Tears on My Pillow", "Why Do Fools Fall in Love" and "Earth Angel".

[11] Melanie Bertoldi of Billboard said, "The midtempo number's undeniably contagious chorus should keep Bieber's tween fan base satisfied, and Ludacris' brief cameo adds a welcome urban twist.

"[12] Bertoli went on to say, "The matchup adds a layer of maturity to Bieber's repertoire and should further solidify his growing presence on the charts.

"[12] Rap-Up magazine said that "the sweet pop fare gets a little street cred courtesy of the teen sensation's labelmate Ludacris.

The instance had last happened in 2003 when American Idol's Ruben Studdard and Clay Aiken's debut singles charted at number one and two.

[15] On the issue dated February 8, 2010, the song debuted in Australia on the official ARIA Singles Chart at number thirty-seven.

[24] The following week, "Baby" fell to number four, but climbed back to its previous peak position of three on the issue date March 28, 2010.

[27] It was filmed at Universal CityWalk and Lucky Strike Lanes, by director Ray Kay, who had previously directed videos for Beyoncé Knowles, Lady Gaga, Alexandra Burke, and Cheryl Cole, among others.

Bieber's friends,[31][32][33] Young Money artists Drake and Lil Twist also appeared in the video, along with Tinashe and jerkin' crew The Rangers.

"[34] The MTV review goes on to say, "most of the video takes place in the bowling alley, there are also scenes of Bieber in other settings, hanging out with Luda, doing the moonwalk, messing with his hair and mugging for the camera.

"[34] Billboard reviewed the video, saying, "Those new dance moves he's showing off can only mean one thing: all over the world, tweens' hearts are melting right now.

[39] He performed the song the first time with Ludacris on BET's SOS: Saving Ourselves – Help for Haiti Telethon, on February 6, 2010, which also aired on VH1, and MTV.

Bieber performed the song along with "U Smile" on the eighteenth episode of season thirty five of Saturday Night Live.

[41] Bieber performed an acoustic rendition of the song along with a freestyle by good friend Drake at the 2010 Juno Awards.

In 2012, Alexa Ilacad, Mika Dela Cruz, Noemi Oineza and Angel Sy, AKA T.O.P., sampled this song for their single "Crush".

[citation needed] Yes We Canberra released a parody version satirising then Opposition leader Tony Abbott during the lead-up to the 2010 Australian federal election.

[48] In the 2012 film Diary of a Wimpy Kid: Dog Days, Greg Heffley's older brother Rodrick (portrayed by Devon Bostick) performs a hard rock cover of the song with his band, Löded Diper, in an attempt to impress his love interest Heather Hills (older sister of Greg's love interest, Holly) during her Sweet 16th party.