Son Maceo, who was born about two months ago, is the second child for Williams and Drake-Lee. They have a daughter named Sadie, who will turn 2 in December.
Williams, 34, and Drake-Lee, a 33-year-old real estate broker, were married in September 2012. They announced over the summer that they were expecting.
While their Grey's characters have had difficulties expanding their family, Williams and his TV wife Sarah Drew have each welcomed children in the past year. Drew gave birth to her second child, a daughter, last December.