Mabel worked with writers and producers such as Tre Jean-Marie, Steve Mac and MNEK to create the album, with its tracks incorporating elements of pop and R&B.

[9] The album's only promotional single, "Bad Behaviour", was released on 23 July 2019, alongside a music video directed by Oliver Kane.

[18] Reviewing the album for musicOMH, Ben Devlin hailed it as "a convincing display of versatility and quality songwriting that firmly establishes Mabel as a force to be reckoned with in UK pop",[21] while Chris Taylor of DIY regarded it as "effortlessly cool" with "no faux-earnestness".

[20] Q magazine's Laura Barton called the album "highly polished" and said the singer "perfected the art of writing songs that even on first listen sound totally ubiquitous".

"[22] Andrew Wright of The Skinny stated that the singer found her individual identity with High Expectations which he described as well-rounded despite "some over-zealous Top 40 attempts".

[1] Conversely, Joe Hale of Clash found it "almost too airbrushed, with Mabel playing it a little too safe to qualify being described as wholly original or progressive", but concluded that it had "some real highlights" and "moments of talent and flair".

[19] Despite finding the album strong and well-crafted, The Guardian's Alexis Petridis also believed it lacked personality and only "occasionally hints its maker might be more interesting and individual".

[2] Kitty Empire was more critical in The Observer, writing, "High Expectations is just disappointingly all right, lacking any playfulness, or top spin, or a sense of who Mabel is,"[23] while Uncut critic Johnny Sharp commented, "Despite some pleasant enough tunes, she lacks the vocal charisma to stand out from other wannabe Rihannas, Mileys and Dua Lipas.

"[26] Mick Jacobs of PopMatters concluded, "Though sung in a beautiful, agile voice, the album's contents lack any innovation that truly set them apart, even amongst themselves.

"[24] High Expectations debuted at number three on the UK Albums Chart, behind Ed Sheeran's No.6 Collaborations Project and Lewis Capaldi's Divinely Uninspired to a Hellish Extent, with first-week sales of 9,761 album-equivalent units.

Mabel announced the album on 28 July 2020, saying "This year turned everyone's plans sideways and I’ve been using the time in my home studio to record an acoustic version of every track.