Krakowski, 42, is best known for her work on TV's "Ally McBeal" and "30 Rock." She is engaged to British clothing designer Robert Godley.
UsMagazine.com said Wednesday the couple's baby was born April 13.
"Bennett is an amazing, healthy, sweet boy and we are both just crazy in love with him," Krakowski told the Web site.
2014: The Year in Music [PHOTOS]