Mr Turnbull said it had been a long and hard-fought campaign that was described by Mr Trump himself as nasty at times.
"I understand that Australians have been confronted by the intensity of the political battle in the US," he said.
Mr Turnbull said the US is a "great nation" had the capacity to come together and it would behind Mr Trump.
"Now, we have no stronger relationship whether it's on the battlefield or in commerce, than we have with the United States."
"They're a great and powerful nation, they're a great and powerful friend."
Americans understood they have no stronger ally, no better friend, than Australia.
"And the enduring national interests of our two countries as such that our relationship will continue to be strong, will continue to work together as we have done, with many presidents in years past to chat, to take on the challenges of our time."
Mr Turnbull acknowledged the great leadership of President Barack Obama and his Vice-President Joe Biden.
"President Obama has guided the United States and led the world through many challenges.
"Challenges of the global financial crisis, dealing with the challenges of terrorism, dealing with the challenges we face in the Middle East, where our servicemen and women are fighting side by side with their American comrades."
Mr Turnbull said he looked forward to working closely with the Trump administration as it is formed and when it takes office earlier next year.
"The American people have made a great and momentous choice today."
The prime minister said it was a historic moment and Australians had been watching the campaign with awe and consternation.
"But let me reassure all Australians that the ties that bind Australia and the United States are profound, they're strong, they're based on our enduring national interests."