The Wonder Years actor took to Twitter earlier in the week to share the first image of his baby son's hand.
"He's here," Savage wrote in a caption accompanying the image.
Savage and Jennifer were childhood friends, prior to their romantic relationship. The couple are also parents to son Oliver and daughter Lily, who were born in 2006 and 2008 respectively.
Savage gained wide fame with his roles as a young boy in the feature films The Princess Bride and Little Monsters and as Kevin Arnold in Wonder Years.
He has in more recent years turned to directing television shows including Party Down, Happy Endings and Modern Family.