The former Abbott government treasurer will start his new Washington DC role in early 2016.
The current ambassador, former Labor leader Kim Beazley, starts a new role with the Australian Institute of International Affairs in January.
Hockey retired from parliament in September and his seat of North Sydney was retained by the Liberals at a by-election on the weekend.
The former treasurer told Sydney businessman Mark Bouris in an interview posted on his website that he was still keen to contribute to public life.
“I still have three or four years of desire to contribute to the country in one form or another,” Hockey said.
“It’s just that politics at the end of the day beat me.
“If I was going to stay, it would be overwhelmingly about getting even with people that brought me down.
“But I love my country and my family more than I hate my enemies.”
Prime Minister Malcolm Turnbull described Hockey on the ABC’s 7.30 program on Monday night as a “great Australian”.
Foreign Minister Julie Bishop said the Australia-US alliance was the “bedrock of foreign and defence policy” and the US is Australia’s largest two-way investment partner.
Beazley has been in the role since 2010.
US President Barack Obama has invited Turnbull to visit the White House before the end of February.
Turnbull said Hockey was “one of the most engaging, persuasive people I’ve known in public life”.
“He’s held very high office. He has great contacts in the United States. He is a passionate patriot but has a good understanding of how Washington works already,” he told reporters in Sydney.
Former senior Australian diplomat Ric Smith said there was a long record of political appointees to Washington going back to the 1940s.
“What the Americans are always interested in is what is this person’s standing in Australia and do they have access to the highest levels of government in Australia,” Smith told ABC radio.
“Can this person pick up the phone to the prime minister, the foreign minister, the defence minster and sort out a problem with them?”
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