Caroline Kennedy handed over her credentials to the governor-general in Canberra on Monday where she hosted the US embassy's first Indigenous welcome to country and smoking ceremony.
Ms Kennedy is due to meet with Prime Minister Anthony Albanese on Wednesday.
"The United States and Australia are the closest allies," she told reporters after the ceremony.
"I'm really looking forward to meeting the prime minister. I haven't met him yet.
"I know (Mr Albanese) had a great meeting with President Biden so I'm looking to follow up on that and see what can best do to advance our shared goals."
Ms Kennedy also pre-empted further announcements on the AUKUS alliance between Australia, the US and the UK when asked about what message she would be bringing to the prime minister.
"There are many announcements that are going to be coming in the coming weeks, so I think it's best to let those unfold," she said when asked about the alliance.
Upon her arrival on Friday, Ms Kennedy admitted the US needs to take up a greater role in the region, as Washington renews its national security strategy in the Indo-Pacific.
"China certainly has a big presence here in the region," she said after landing.
"The US needs to do more. We're putting our embassies back in and the Peace Corps is coming, and USAID is coming back.
"It's certainly a big focus now. This is a critical area in the region."
The ambassador also confirmed she would be travelling to the Solomon Islands with US Deputy Secretary of State Wendy Sherman at the end of next week.
Ms Kennedy's ambassadorship was unanimously confirmed by the US Senate in May and she was sworn in on June 10.
The author and lawyer succeeds Arthur Culvahouse, who left the position in early 2021, when Republican president Donald Trump left office.
She is the daughter of assassinated US president John F Kennedy and previously served as US ambassador to Japan.
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