Upon its release, "What the Hell" received positive reviews from music critics with many complimenting its catchiness and comparing it to her 2007 single "Girlfriend". The song was successful, reaching number one in Japan, the top five in Asia, the top ten in Europe, Australia, South America, Mexico, Canada, and the top 20 in the US and the UK.
An accompanying music video for the song was directed by Marcus Raboy and premiered on 23 January. "What the Hell" was performed by Lavigne on several television programs such as Dick Clark's New Year's Rockin' Eve, Daybreak, The View, The Tonight Show with Jay Leno and on the Much Music Video Awards, America's Got Talent and Britain's Got Talent. Additionally, she added the song to the setlist of the Black Star Tour (2011).