Mr Beazley will replace council chair Brendan Nelson, who will step down at the end of November to take up a role with Boeing in London.
The former opposition leader is expected to fill the council vacancy for three years.
Veterans' Affairs Minister Matt Keogh congratulated Mr Beazley on his appointment.
"It's (the spirit of keeping alive the memory of the price we paid for freedom that) Kim will bring to our nation's most sacred memorial," Mr Keogh said.
"(He will make) sure defence members, veterans and those who made the supreme sacrifice are properly honoured and remembered."
Mr Beazley was one of the country's longest-serving defence ministers when he was part of Bob Hawke's government.
Mr Keogh paid tribute to Mr Beazley's five years in the role as defence minister, which included helping to establish the navy's submarine program.
After leaving politics, Mr Beazley served as Australia's ambassador to the United States.
The War Memorial's council meets four times a year and is made up of 13 members.
Other members of the council include former prime minister Tony Abbott and Victoria Cross recipient Corporal Daniel Keighran.
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