[3] The album was produced in various locations during lockdowns imposed as a result of the COVID-19 pandemic, and features songs co-written by Albert Hammond Jr., Romeo Stodart, KT Tunstall, Eg White, Fiona Bevan, and Rachel Furner, among others.

"[21] Shaad D'Souza from The Guardian said the album "is delightfully unburdened: a carefree survey of pop and rock trends that re-establishes the fact that, at her best, Imbruglia is a canny lyricist and an incisive, whip-smart writer of hooks.

"[22] Retro Pop called the first half of the album "endearing" but said "it wears thin over the course of 14 songs, with the latter portion of the record meandering without ever gaining pace."

They concluded saying "There's no doubt about it, Natalie Imbruglia is a brilliant pop star, and it's unfortunate she settled on such an exhaustive release – because buried within Firebird is a stellar 10-track album.

"[14] Rachel Alm from Riff Magazine said "Many of the songs on Firebird sound very close to contemporary country and could have even benefited from leaning into that a bit more."