Chlumsky, 32, starred in the 1991 film "My Girl," and earned an Emmy Award nomination Thursday for her performance in the sitcom "Veep."
People.com said Chlumsky gave birth July 11 to her first child with entrepreneur Shaun So, whom she married in 2008.
"She's a really good mix between my husband and me," the actress told the magazine about her new baby. "When she's with him, you see him, and when she's with me, you see me. She's a perfect mix. We think she has my mouth, but it's hard to tell. Even the color of her eyes, they are different in different light. But she has a really full set of hair."
Chlumsky said she is "still in shock" after hearing about her Emmy nomination.
"When I got the call I wasn't sleeping because I was breastfeeding my daughter," she told People.com. "It was neat because it was me and my husband and my daughter all in the room getting the news at the same time. When [my manager] told me, it was that nervous, happy, appreciative laughter. I just laughed a lot! It feels really great to have your work noticed."