Emerson, the couple’s first child, was named in part after Ralph Waldo Emerson.
Miller made her Broadway debut in Sister Act in 2011 before going on to win a Tony Award two years later for her performance as the Leading Player in Pippin. Since then, she has appeared in the Hunger Games series, Mercy Street, and currently, the CBS drama Madam Secretary.
Miller and Mars, a venture capitalist, were wed in June 2014 in Long Island City. They announced their pregnancy in March.