He attended Moreland High School in Coburg, Victoria,[6] where "a history teacher fuelled his interest in politics by slipping him copies of socialist literature to read at home".

When retiring Senator John Button resigned before the expiry of his term, however, Carr was appointed to the resulting casual vacancy on 28 April.

[10][11][12][13] His influential position within the party has attracted substantial criticism from factional opponents, Carr was then described by colleagues as "ruthless", "calculating" and a "headkicker".

[14] Carr was re-elected in the 2010 election and retained his portfolio of Minister for Innovation, Industry, Science and Research in the Second Gillard Ministry, which was sworn in on 14 September 2010.

[18] Carr resigned his ministerial portfolio on 22 March 2013 after he supported an unsuccessful attempt to reinstall Kevin Rudd as Labor Leader.

In response, Carr formed his own mini-faction, the Industrial Left, which was recognised by Shorten's Labor Right, allowing him to remain in the shadow ministry.

It was reported in early March 2022 that he had lost the support of unions in the Industrial Left faction and was set to miss out on the Senate ticket.

However, following the recent death of fellow Senator Kimberley Kitching and "determined urgings" from his children, he announced on 27 March 2022 that he decided to retire at the election, citing health reasons.