They are often supplemented by The Empire Horns, a brass duo composed of Ross Irwin (trumpet) and Kieran Conrau (trombone), among others.

The band expanded in July 2001 by adding Harry James Angus on trumpet, Will Hull-Brown (ex-Jazz Cat) on drums and Jamshid "Jumps" Khadiwala as a DJ on turntables (later also on percussion).

The ensemble commenced its first overseas tour on the West Coast of the United States, playing at The Matrix in San Francisco and at the Napa Valley Wine Auction in June.

The band received a Music for the Future grant to fund the recording of a live album, The Sun, at Melbourne's Adelphia Studios.

They performed at the 2002 Melbourne Festival and a series of local gigs; Kate Ceberano appeared as a guest vocalist at their final show for the year.

The group's growing live and critical reputation enabled them to approach record companies for a deal to issue the album in August.

It was recorded in Havana, Cuba, at Egrem Studios, late in 2004, with production by the Cat Empire, Riebl and Jerry Boys.

AllMusic's Jeff Tamarkin wrote "Skipping merrily from alt-rock crunch to hip-hop beats, landing on reggae/ska, Latin jazz, and points in between, Two Shoes is clever and brainy, danceable and absorbing".

[6] Described by the group as "between a tribute to our own city and an experiment in sounds that we've found abroad",[13] a limited edition of 10,000 individually numbered copies were made available.

In June, on the group's European tour, they appeared on the Avalon Stage at the Glastonbury Festival, where the mud was so deep that Riebl and Khadiwhala performed the "gumboot shuffle".

The Cat Empire released their fourth album, So Many Nights in Australia on 22 September 2007, it was produced by John Porter and reached number two.

In February 2008, the band concluded their Outdoor Australian Tour, with performances in Sydney, Melbourne, Perth, Newcastle, Canberra, Geelong, Townsville and Launceston.

In March, the band headlined on the Sunday night at the East Coast Blues & Roots Music Festival in Byron Bay.

On 28 February, the band played two free shows at Bondi Beach and Circular Quay, welcoming donations, in an effort to raise funds to be put towards the Victorian Bushfire Appeal.

[20] "Brighter Than Gold", the first single from their sixth album, Steal the Light, was released on 22 February 2013 on the Two Shoes music label.

The band performed nine US shows in July 2013, supported by Blackalicious and, for some of the American dates, were joined by fellow Australians Tinpan Orange.

[24] In February 2014, the Romanian B’ESTFEST Summer Camp announced that the Cat Empire was the first band to confirm their position on the event's musical lineup.

[25] On 16 January 2015, the Cat Empire performed at Triple J's 40th anniversary "Beat The Drum" celebration concert at the Domain in Sydney, along with other Australian musicians, including Hilltop Hoods, The Presets, You Am I, Daniel Johns, Vance Joy, The Preatures, Ball Park Music, Sarah Blasko and Gotye.

In early 2016, the Cat Empire announced their second fully independent album, Rising with the Sun, produced by Jan Skubiszewski.

On the week of release, the band performed a series of secret 'pop up busking' events around Melbourne, with locations given to fans via clues shared on social media.

Internationally successful, the album achieved Top 10 debut in 7 countries, and Top 20 debuts in 16 countries: #1 Australia, #1 Romania, #4 Hungary, #7 Sweden, # 8 Canada, #9 Czech Republic, #10 Switzerland, #13 Malaysia, #13 New Zealand, #14 Netherlands, #17 Germany, #18 Denmark, #18 South Africa, #19 United Kingdom, #20 Portugal, #20 Spain.

Rising With the Sun was supported by an extensive global tour, with close to 100 shows booked[29] across Australia, Europe, America, and Asia for 2016.

In early 2018, the Cat Empire recorded their third fully independent album, Stolen Diamonds, at Red Moon Studios[34] (Gisbourne, Victoria), also their third to be produced by Jan Skubiszewski.

With a history of putting fans in the spotlight, lead singers Riebl and Angus hand-delivered copies of the album to fans on release day,[46] and also gave them opportunities to put their own spin on the music with a Karaoke competition[47][48] for the track Oscar Wilde, and a Busking competition[49] that included an entry from long time friends of the band, Pierce Brothers.

During this time, they launched a social media initiative, #lockdowngetdown, encouraging listeners to make playlists using their favourite music and share them with others, in an effort to support artists who had lost their source of income due to the impact of the pandemic.

[66] In April 2021, the band announced via their Facebook page that they had entered the recording studio to work on a new album, with Yuri Pavlinov of The Bamboos filling in on bass.

[72] The band started their farewell tour with two shows at the Sidney Meyer Music Bowl in December 2021, for which they were rejoined by former bassist Ryan Monro.

[77] On 16 August 2024, it was announced that the Melbourne leg of the tour was indefinitely postponed in solidarity with pianist Jayson Gillham's performances being cancelled due to differing political views.

[79] During the first half of 2024, the band toured across Europe and North America, including their fourth appearance at Glastonbury Festival,[80] and their first performance in Alaska.

In response to the proposed dumping of around 3 million cubic metres of dredged seabed onto the Great Barrier Reef,[83] a legal fighting team was formed by World Wide Fund for Nature (WWF)-Australia and the Australian Marine Conservation Society (AMCS) in late 2013/early 2014.