Molly gave birth to a daughter the couple named Riley Anne Mesnick in Seattle, WA on Thursday, Peoplereported.
"What's amazing to me is when Molly is holding Riley, her eyes do not come off her," Jason told People. "I'm already seeing how much Molly loves the baby."
"Daddy's little girl" reportedly arrived in the afternoon weighing six pounds and eight ounces. According to Jason, the baby is nearly 18 inches long and "has a full head of hair -- probably more than I'll have in the next few years."
Riley joins eight-year-old Tyler, Jason's son from his first marriage.
"Ty has been asking for a sibling for so long," Jason said. "He was here earlier holding her and kissing her and it was really, really cute. We're so happy."
Jason explained he massaged Molly's feet -- the area between the ankle and the Achilles tendon -- Wednesday night after a friend had texted him suggesting the gesture would help her go into labor.
"I did it last night for about three minutes and Molly woke me up at about three this morning, after she'd been up for about an hour and a half, so maybe it does work?" Jason questioned.