Mattiel is a music project fronted by Mattiel Brown and previously produced by Jonah Swilley. They have released three albums, Mattiel in 2017, Satis Factory in 2019 and Georgia Gothic in March 2022, alongside three EPs: Customer Copy (2018), Double Cover (2020) and Those Words (2021). All releases came out on the British record label Heavenly Recordings in the UK and Europe and on ATO Records for the US (except for Mattiel, which was released by Burger Records in the US).

Mattiel has been championed by Jack White, and they toured together for a series of arena shows around the US in April of 2018. Rolling Stone compared Brown's “gorgeously yearning, full-voiced alto range” to Nico, while NPR wrote: “There's something delightfully unique about Mattiel's music. A pinch of garage rock, a touch of psychedelia, some galloping honky-tonk and at the lead, Mattiel Brown's powerful and assertive vocals.”

Sophomore album Satis Factory received four-star reviews from The Guardian, Q, Mojo, DIY, Uncut, and The Times, and was named Album of the Weekend by BBC Radio 1 Hype Chart and A-listed as Album of the Day on BBC Radio 6 Music. Mattiel was also listed as WXPN Artist of the Month.

In addition, Mattiel has also performed on Later... with Jools Holland and Last Call with Carson Daly, and featured in The BBC Proms at the Royal Albert Hall, London. Most performances are posted on Mattiel's YouTube channel, as well as Brown's southern gothic style music videos, the newest of which for the song Blood in the Yolk was inspired by 1970s middle eastern gothic styles.

In Spring of 2023, Mattiel Brown released a version of Moon River with Jeff Goldblum and his jazz band, The Mildred Snitzer Orchestra. She performed with Goldblum live in New York City and through Europe, appearing on Late Night with Seth Meyers in the US, as well as This Morning (TV programme) and The Jonathan Ross Show in London.