Jax Copeland Arnold was born at 9:53 a.m. Saturday, People reported, and measured in at 8 pounds, 12 ounces and 21 inches long.
"We are still in a bit of shock," the proud new parents said. "It has been a long journey and the healthy birth of our son is a miracle."
The couple, who have been married since November 2009, had infertility problems before resorting to in vitro fertilization, People said.
Arnold, who was married three times previously, is 54. Groussman has previously been reported to be 17 years younger.