The video, which is over six minutes long, features the band going into an office in Hollywood and talking to two executives named Harvey and Johnny (Niall Horan and Louis Tomlinson, respectively) after being led in by Veronica, the sexy assistant (Zayn Malik). Marcel, the nerdy marketing guy (Harry Styles), shows them photoshopped pictures of the band in ridiculous outfits and even has a choreographer named Leeroy (Liam Payne) demonstrate his ideas for new dance moves. Insulted by this attempt to box them into the boy band stereotype, the band erupts into the song and starts wreaking havoc by throwing things around the office. Interspersed with clips from their film, This Is Us, the band continues to destroy the office and even shows off a "dance routine," poking fun at their perceived lack of dancing prowess. The video ends as they nail a poster of themselves to the wall and Zayn spray paints the words "this is us" on it, presumably to let people know that they will continue to be themselves despite their growing success and popularity.
The video broke the Vevo 24-hour record with 12.3 million views, although the record was later broken by Miley Cyrus's "Wrecking Ball", which garnered 19.3 million views.
"Best Song Ever" received mixed to positive reviews from contemporary music critics. Amy Sciaretto of PopCrush awarded the song 3 and a half out of 5 stars, stating that "the first 20 seconds and intro of the song" were likely an "intentional homage" to The Who's "Baba O'Riley", however that the rest of the song was "signature 1D". Sciaretto went on to call the song "flirty, fluffy, and fun", dubbing the track "anthemic" and "cute", however stated that the song was not as catchy as their previous singles "Live While We're Young" and "Kiss You" and that it wasn't their best work.Click Music reacted negatively to the song, giving it 1 and a half stars out of 5, describing it as "tiresome" and called the song's writers "creatively barren", accusing them of plagiarism of The Who's "Baba O'Riley". It also called the song a representation of "the laziest, most mind-numbing trends in modern pop".
Giving the song 4 and a half stars, Bill Lamb of About.com wrote: "It is not THE "Best Song Ever," but this is arguably One Direction's best song ever, and that is a very good thing." He called the song loose, playful, and all in good fun; a great intro to their new album, and the best of past One Direction concentrated in one song. He noted the beefed-up production giving it a pleasing rock feel. "Pros: Upbeat, playful energy, Charm that induces smiles, Classic rock references. Cons: No mistakes here."Popdust's Samantha Martin stated that the song did not "live up to its titular goal", and that some of the song's lyrics were contradicting. Martin described the song as a youthful "celebration", stating it was "definitely for the kids" and stated it wasn't their best work, however nonetheless described the song as "fantastically catchy" and praised Zayn Malik's "falsetto shriek" at the end of the song and compared the song's use of the name Georgia Rose to The Beatles.
The group performed the song live for the first time on 30 July 2013 at the SAP center in San Jose, California during their Take Me Home Tour concert. The song was added to the setlist of the concert to all proceeding shows of the American leg. The groups first televised performance of the single was at the 2013 Teen Choice Awards on 11 August. The group also performed the song, along with some of their other hits, on The Today Show on 23 August and on America's Got Talent on 28 August, and again on the The X Factor Australia on 27 October. On 1 November, they performed the song again on the Japanese music show Music Station. They performed it for the first time on British television on November 15 at Children in Need 2013.