Steele is the vocalist and primary songwriter of the alternative rock band the Sleepy Jackson and is a member of the electronic music duo Empire of the Sun.

In 2006, Steele became engaged to a magazine editor, Jodi (aka "Snappy Dolphin"),[4] who also joined the Sleepy Jackson for the band's 2008 national tour.

[7][8] The Sleepy Jackson were established in 1998, featuring Steele on vocals and guitar, his brother Jesse on drums and Matthew O'Connor on bass.

In addition to playing solo shows, Steele recruited Malcolm Clark (drums), Justin Burford (guitar) and Rodney Aravena (bass).

Songs from this EP, and Caffeine in the Morning Sun, were compiled into a self-titled mini-album for release in the UK market in February 2003.

Joining Steele and Clark on this album were Dave Symes and Felix Bloxsom, as well as Lee Jones (formerly in the Perth band Spencer Tracy).

Also in 2007, Luke provided slide guitar on the song "Waiting All Day" by Silverchair on their fifth album Young Modern.

[11] The pair only decided to get serious about making an album in 2004 when Steele went to Littlemore's studio north of Sydney and they began writing material together.

For the next few months, the pair continued to write songs for the project independently and organised meetings in Sydney to decide on the album's overall musical direction and style.

[19] In his review for NME, Martin Robinson described their debut as "silly but their songs demand to be taken seriously, just like Prince, Ultravox and Bowie.

Dorian Lynskey of The Guardian rated it 3 out of 5 stars, applauding the duo's unpredictability, but wishing "they would calm down a bit".

[24] The album's release was preceded by a trailer directed by J. D. Dillard of Kelvin Optical, Inc. (a division of J. J. Abrams's Bad Robot).

[26] Steele received global media attention following an interview with music publication NME at the Sziget Festival in Budapest, in August 2013.

During the interview, he compared Ice on the Dune to Daft Punk's 2013 Random Access Memories, saying: "They had a great marketing campaign, but we’ve got better songs.

In October 2014, Empire of the Sun headlined Sandance at Dubai's Atlantis the Palm[28] and in fall 2015 undertook a brief world tour.

[30] Steele cites his musical influences as including The Cure, Elliott Smith, Paul McCartney, Michael Dempsey, John Lennon, Robert Smith, Brian Wilson, Carole King, James Taylor, The Four Freshmen, Kool and the Gang, Roger O'Donnell, and Cole Porter.

[32] While in New York City in 2006, Steele contributed a track called "I'm Moving On" to Yoko Ono's 2007 remix album Yes, I'm a Witch.

[33] Steele described the project: "It kind of started out a White Album thing because we don't have a band, it was acoustics.

"[34] In August 2008, Steele embarked on his first national solo tour and performed—in an intimate acoustic guitar mode—songs from both the Sleepy Jackson albums, as well as a selection of new songs from his other projects.

[36]Steele co-wrote and co-produced the track "Rather Die Young" on American R&B singer Beyoncé Knowles's 2011 album 4.

[39] Steele teamed up with Daniel Johns of Silverchair to form the band DREAMS, releasing the single "No One Defeats Us" on 16 March 2018.