The actor and his wife, Desiree Gruber, a movie producer, welcomed their first child last Friday.
Callum Lyon MacLachlan weighed 8 pounds, six ounces, and both he and his mother are doing well. His father, who plays Orson Hodge on Desperate Housewives, and his mother have been married for six years.
MacLachlan can be seen in a few weeks in the film Sisterhood of the Traveling Pants 2. Desperate Housewives will begin a new season in the fall.