“I’m proud of the fact that we tried three times to get an emissions trading scheme through this Parliament, although we failed,” Mr. Rudd told reporters.
“I’m less proud of the fact that I have now blubbered,” he joked, as he struggled to contain his tears.
He said he would contest the next election and continue to serve the government “in any manner in which I can be of assistance.”
Ms. Gillard and her new deputy, Wayne Swan, were sworn into their offices by Australia’s first female governor-general, Quentin Bryce, within hours of the ballot.
Mr. Swan retains his key financial portfolio as treasurer and will to fly to Canada on Friday for a summit of Group of 20 major economies in Mr. Rudd’s place. He was also elected unopposed. Ms. Gillard has yet to announce any other ministers in her new Cabinet.
Ms. Gillard has been instrumental in most of the government’s decisions to date as part of Mr. Rudd’s four-member inner circle that included Mr. Swan and Finance Minister Lindsay Tanner. Mr. Tanner announced on Thursday he was quitting politics at the next election for personal reasons.
John Wanna, an Australian National University political scientist, blamed Mr. Rudd’s style and inability to clearly communicate for his plummeting popularity.
“He’s not been a bad prime minister, but he comes across as a smarty pants, policy wonk and when he does the human face stuff, he seems a bit disingenuous to the ordinary person,” Mr. Wanna said.
Mr. Wanna said dumping Mr. Rudd for Ms. Gillard — widely regarded as the best communicator in Parliament — months out from an election was risky for the government.
“We’ve got rid of a successful prime minister after two and a half years, and we’ve never done that before in the past,” Mr. Wanna said.
Ms. Gillard was born in Barry, Wales, in 1961, the second daughter of a family who migrated to Adelaide when she was 4 years old in search of a warmer climate for a lung condition.
A former successful lawyer and state government political staffer, she has been attacked by some opponents as unsuitable to lead because she is childless and therefore out of touch with most Australians.
Despite Australia’s weathering the global downturn, recent polling puts the center-left government neck-and-neck with the conservative opposition. One poll earlier this month showed Labor trailing the opposition for the first time in more than four years.
Mr. Rudd is a Labor hero, having led the party to victory at 2007 elections after 11 years in opposition.