[3] Noonan grew up with a strong background in classical music, with her mother Maggie being a well-known opera singer.

Noonan founded George with her brother, with whom she shares lead vocals, in 1996 to enter a university music competition.

The reviewer Murray Black said that "The undoubted highlight of the evening was guest vocalist Katie Noonan.

Then, in Gollum's Song and the Oscar-winning Into the West, she revealed her pop diva credentials with her strong, clear voice projecting effortlessly out in the audience.

Consisting of words written by Dorothy Porter, the album tracks "the mysterious shifts and changes of a relationship".

Later in 2005, Noonan was invited by Deborah Conway to take part in the Broad Festival project—together with three other Australian female artists they performed their own and each other's songs.

The collaboration involved the re-recording of Noonan's vocal tracks and a dance version of her solo album was released under the title Second Skin.

Noonan wrote all of the songs and collaborated with the following artists during the recording of the album: Tim Finn (Split Enz), Sia, Don Walker (Cold Chisel), Josh Pyke and Australian writer/poet Tom Shapcott.

The album was co-produced by Noonan and Nick DiDia (Pearl Jam, Bruce Springsteen, Stone Temple Pilots, Powderfinger).

The album due for release in February 2017 and will see the duo embark on a musical journey through the South American songbook, exploring the sounds and beats of the bossa nova, salsa, tango and samba.

In April 2019, Noonan released The Little Green Road to Fairyland with Camerata and the Queensland Chamber Orchestra.

The new album sees Noonan perform uniquely Australian poetry of Queenslander and First Nations icon Oodgeroo Noonuccal to music.

[16][17] In January 2020, Noonan confirmed the release of a mini-album titled Late Night Tunes with Noons.

In January 2023, Noonan commenced a national tour of 40 concerts, performing the entirety of Joni Mitchell's seminal album Blue, marking the 50th anniversary since its release.

A National Office for Live Music was launched by Australian Prime Minister Kevin Rudd in July 2013 and, as of August 2013, Noonan is the state ambassador for Queensland.

[27] On 25 September 2022, Noonan sang the National Anthem at the opening of the 2022 AFL Grand Final at the Melbourne Cricket Ground.