Goldfrapp described the album as a "sensual counterpoint to the glitterball glamour of Supernature", their previous studio album from 2005. They claimed that the inspiration came from paganism and surreal English children's books. The album received rave reviews and became the band's most critically acclaimed album since their 2000 debut Felt Mountain, with critics praising their new sound and the band's bravery for abandoning the dance atmosphere of the previous two albums.
The album's first single, "A&E", was released on 11 February 2008, charting inside the top ten in the UK. The album also charted high in the UK, peaking at number two, despite having leaked onto file-sharing websites in November 2007, three months before its official release.
Seventh Tree received generally positive reviews from music critics. At Metacritic, which assigns a normalised rating out of 100 to reviews from mainstream critics, the album received an average score of 78, based on 32 reviews, which indicates "generally favorable reviews". John Murphy of musicOMH called it Goldfrapp's "most subtle, affecting and rewarding album to date" and compared it to albums by Kate Bush and the Cocteau Twins. In a review for Allmusic, Heather Phares wrote that the album's "electro hippie-chic is the duo's most polished and luxe work yet" and named "Caravan Girl" as its best song. However, Pitchfork Media reviewer Nate Patrin was less impressed, and wrote that the album is "so subtle and slow-moving it doesn't seem to go anywhere" and that its songs "coast on some frothy sense of pleasantness that evaporates the moment [they] end". Adam Webb of Yahoo! Music wrote that Seventh Tree "marks convincing evidence that Alison Goldfrapp now exists on the same artistic plane as PJ Harvey or Kate Bush".Rolling Stone's Christian Hoard said that the "slow pace can be a snooze", but that the album "still makes for good post-party chill-out music". John Lewis of Uncut called it "brave, bonkers, often beautiful, sometimes haunting and occasionally ridiculous".
Q magazine ranked the album at number nineteen on its list of The 50 Best Albums of 2008.PopMatters placed it at number fifty-four on its list of The Best Albums of 2008.Ben Rayner of the Toronto Star included the album on his list of "rock music that stuck in 2008".
Seventh Tree debuted on the UK Albums Chart at number two, selling 46,945 copies in its first week. It remained on the chart for thirteen weeks and was certified gold by the British Phonographic Industry within four days or release, on 29 February 2008. It sold 177,000 copies as of late 2008. As of 27 March 2010, the album had sold 200,062 copies in the UK. The album reached the top twenty in Australia, Belgium, Ireland, Norway, Portugal and Switzerland.Seventh Tree became Goldfrapp's second release to chart on the Billboard 200 albums chart in the United States, where it debuted at number forty-eight with first-week sales of 15,000 copies. Additionally, the album reached number four on the Tastemakers chart, number seventeen on the Top Internet Albums chart, number twelve on the Top Alternative Albums and number fourteen on the Top Rock Albums chart. In Canada, the album reached number twenty-eight.
A special edition of Seventh Tree was released on 3 November 2008, featuring new album artwork, photographs and a DVD. The album artwork depicted Goldfrapp dressed as a clown and hugging a tree, as well as Gregory dressed as an owl. The DVD contained music videos, behind-the-scenes footage and several live performances filmed at The De La Warr Pavilion in Bexhill-on-Sea in June 2008.