"Everything was being driven by grunge or techno, then suddenly these people arrived and did something which was completely different and happy and simple. I just think they write brilliant pop tunes and it hit a nerve at the time. (...) I think they've developed their own style. If you listen to the radio and you hear a record, you immediately recognise that it's Ace of Base."
—Managing director of Metronome Records, Albert Slendebroek talking to Music & Media about the album.
Happy Nation was released in 1992 in Scandinavia and early 1993 in the rest of Europe, Africa, and Latin America on Festival Records. It reached the number one position in at least 14 countries, and has sold over 23 million copies worldwide.
A second release in Europe, Happy Nation (U.S. Version), came on September 25, 1993, to coincide with the album's release in North America under the title The Sign. The Sign was released in North America on November 23, 1993. Despite its title, Happy Nation (U.S. Version) was never released in the United States. Both versions have revised track listings.
These releases include new tracks, including "The Sign", and "Hear Me Calling", "Living in Danger", and the Tina Turner cover "Don't Turn Around", along with alternate versions of other tracks. Certain songs included on the original Happy Nation were removed altogether. The re-release climbed to number one in the UK Albums Chart, beating the number 21 peak of the original release.
The Sign is listed among the Top 100 Best-selling Albums of All Time by the Recording Industry Association of America (RIAA). Several songs on the album became Number One singles in the United States, Europe, and North Africa, including "The Sign", "All That She Wants" and "Don't Turn Around".
In 2016, Russian label Mirumir released an "Ultimate Edition" on vinyl containing the original track list from the 1992 release, the additional tracks from The Sign/Happy Nation (US Version) releases and the iTunes bonuses from the three releases.