[10][11] In 2003, Garrett was appointed a Member of the Order of Australia, "for service to the community as a prominent advocate for environmental conservation and protection, and to the music industry.

At the closing ceremony of the 2000 Olympic Games in Sydney, the group performed before then-Prime Minister, John Howard, and a television audience of hundreds of millions, wearing black overalls bearing the word "sorry".

He served as an adviser and patron to various cultural and community organisations, including Jubilee Debt Relief, and was a founding member of the Surfrider Foundation.

After the Asian tsunami on 26 December 2004, Garrett joined the other members of Midnight Oil to perform as part of the fund-raising event WaveAid.

On 14 March 2009, Garrett performed live at the Melbourne Cricket Ground with Midnight Oil for Sound Relief, in order to raise money for the Victorian bushfire appeal.

[24] In November 2012, Garrett and Paul Kelly inducted Yothu Yindi into the ARIA Hall of Fame and performed with the band their best-known song "Treaty".

[25] On 5 May 2016, after the conclusion of his career in Parliament, Garrett announced that Midnight Oil would be reforming and that they would be touring in 2017, including a trip to the United States.

[33] After the conclusion of Garrett's term as President of the Australian Conservation Foundation ended, in June 2004 Labor Leader Mark Latham announced that Garrett would become an Australian Labor Party candidate for the House of Representatives at that year's federal election, in the safe New South Wales seat of Kingsford Smith which was being vacated by the former Cabinet Minister Laurie Brereton.

There was some initial criticism from Labor members within the electorate, as the local branch had wished to select their own candidate;[34] in the end, Garrett was comfortably elected for the seat in October 2004.

In 2015, Garrett alleged in his autobiography and an ABC documentary that he had been handed an envelope containing "hundreds, if not thousands, of dollars" in cash by a representative of Clubs NSW at a function following the 2004 election.

[41] While some in the media labelled him a "turncoat", some, such as Eureka Street and the Canberra Times columnist and ANU academic John Warhurst, defended his need to be a "team player" if he was going to succeed in the political game "from the inside".

[43] Garrett supported Rudd in that month's leadership spill, a decision he would later come to regret, saying years later that it was "certainly the biggest mistake" he made in his political career.

[49] This move attracted strong criticism from some environmental groups, who were concerned that the 23 million cubic metres of sand, rock and contaminated silt dredged from the bay's shipping channels would affect fishing and tourism in the area.

[50][51] Garrett also refused federal funding that would have enabled a remount of Elke Neidhardt's acclaimed Adelaide production of Der Ring des Nibelungen in 2008.

Although the case was concluded after Garrett had left politics, the ICJ eventually announced its judgement, based on his application, that Japan must stop whaling in the Southern Ocean.

[59] In 2009, Garrett chose not to give the proposed A$2 billion Tamar Valley mill approval until more studies were undertaken on its potential impact on marine environments.

For Rudd and his office to position Garrett as the fall guy was disgraceful, weak, sneaky, unprincipled and just plain wrong.

[70][71][72] In February 2012, Garrett, alongside Indigenous Affairs Minister Jenny Macklin, announced an expansion of the Improving School Enrollment and Attendance through Welfare Reform Measure (SEAM), a program through which parents of indigenous students in the Northern Territory can have their Centrelink payments suspended for three months if their children are not attending or enrolled in school.

In 2013, Garrett pledged to increase funding to public schools as recommended in the Gonski Report, in order to reduce inequality in educational performance.

He noted that the National School Chaplaincy Program needed to change their guidelines because "the line between chaplains acting to support students in the provision of general pastoral care and proselytising was too easily crossed".

After the June spill, where Rudd defeated Gillard, Garrett immediately announced his resignation as Education Minister, and the following day declared that he would not seek re-election at the 2013 election, ending his career in Parliament after nine years.