The engaged couple welcomed their first child, a daughter, on Tuesday, Oct. 3 in New York City, reports People
"Everyone is healthy and happy," says Gyllenhaal's rep, Amanda Silverman. The baby's name is Ramona.
Gyllenhaal, 28, and Sarsgaard, 35, have been together for four years and have been engaged since April.
Although they've both appeared in high-profile studio films, they've made the biggest splashes in indie movies. Gyllenhaal is the older sister of "Brokeback Mountain" star Jake Gyllenhaal. They co-starred in the cult favorite "Donnie Darko," but she really made a name for herself as the titular submissive in 2002's "Secretary" opposite James Spader.
Sarsgaard may be more familiar to mainstream audiences. His recent studio films include "Jarhead," "Flightplan" and "The Skeleton Key." His other film credits include critically acclaimed roles in "Boys Don't Cry," "Shattered Glass," "Garden State" and "Kinsey." He's currently filming the upcoming adapation of Michael Chabon's novel, "The Mysteries of Pittsburgh."