Tenyson Spencer Crowe was born early Friday at Sydney's Royal North Shore Hospital weighing eight pounds, according to manager Grant Vandenberg.
"Mother, father and baby are doing extremely well," he said.
It is the second child for the celebrity couple, and a brother for their firstborn, 2-year-old Charlie.
Crowe, who won an Oscar for his role in the 2000 film "Gladiator," married Spencer in a star-studded Australian wedding in 2003.
Earlier this year, Crowe told U.S. TV talk show host Jay Leno that he and Spencer were expecting a boy, and that they had shared the news with their toddler son.
"He knows where the baby is in Mommy's tummy and knows that he was a baby once and there's another baby coming along," Crowe said. "And we said, 'Bubba, what do you want to call your brother?' and his first option was Pumpkinhead. But then the next day, he revised it and he changed it to Stinky."
Crowe, who was born in New Zealand and raised in Australia, said he would be in the delivery room with a video camera when the baby was born.