Ms Kennedy is due to arrive in Australia on Friday after her ambassadorship was unanimously confirmed by the US Senate in May and she was sworn in on June 10.
The nascent ambassador says the bilateral relationship has reached "a critical time in history" as the two countries battle climate change and increasing volatility in the Indo-Pacific.
"What we do together in the next few years will determine the future of the region and the planet," she said in a video message.
"I look forward to working closely with ... the government to advance our shared democratic values, strengthen our commitment to a healthy, peaceful and prosperous Indo-Pacific.
"We each must be prepared to stand up for what we believe in if we want to pass these precious values on."
Ms Kennedy, the daughter of assassinated US president John F Kennedy, says she wants to carry on her father's legacy.
"He wanted to be the first sitting president to visit Australia so I'm honoured to carry his legacy forward in my own small way," she said.
Ms Kennedy says she wants to learn about First Nations culture and traditions, the incredible natural environment and abundant natural resources.
"When my husband and I got married 36 years ago, we came to Australia on our honeymoon. We always dreamt of coming back," she said.
"We brought our three children in 2014. We fell in love with the people we met and the places we went, and I can't wait until my new grandson comes to visit."
