The actress, who stars as studio exec Dana Gordon on the hit HBO series, married director Russ Lamoureux on Saturday at the SoHo House in L.A.
"Having a wedding ceremony in a rooftop garden high above Sunset Boulevard with your closest friends watching you come down the aisle, it was just overwhelming, in a good way," Zimmer tells PEOPLE exclusively. "I have to say, it was a night we didn't want to end."
Surrounded by family and guests including Tiffani Thiessen, Sarah Chalke, Busy Philipps and Julie Bowen, Zimmer wore a vintage re-creation by L.A. designers Karen Zambos and Nony Tochterman of Petro Zillia.
"When the ceremony was over everyone popped into a photo booth before heading downstairs for a family-style dinner," Zimmer says. "We had drinks while the sun went down. No one wanted to leave. We curled up on the giant velvet couches that lined the windows to eat our cookies and milk."
The couple, who dated for four years, were engaged in June and have a 2-year-old daughter, Colette Zoe.
Zimmer will next be seen in NBC's upcoming series, Love Bites.