Here are some of the moments PEOPLE witnessed from inside the ceremony.
Backstage, the night's big names like Uzo Aduba and Kevin Spacey all shared fun moments with Life Achievement Award honoree Carol Burnett. "I had to remember to breathe," the Orange Is the New Black star was overheard telling a friend.
Double winner Idris Elba proudly carried his actor statuettes, even pretending to use them for weightlifting. "They're going to be weights!" he told PEOPLE.
Brie Larson accidentally hit herself with her latest award. "I'm shaking. I feel so loved and tearful," she said before sharing, "Ow!"
And her Room costar Jacob Tremblay was the star of the evening. After meeting Leonardo DiCaprio, the 9-year-old also mingled with Demi Moore and Rachel McAdams.
Following the 2-hour ceremony was the Screen Actors Guild Awards Gala hosted by PEOPLE and the Entertainment Industry Foundation. L'Oréal Paris and Dunkin' Donuts sponsored the after-party.
Kaley Cuoco had the right idea swapping her Jimmy Choo heels for bedazzled sneakers to dance up a storm with Quantico's Priyanka Chopra.
The late Whitney Houston's "I Wanna Dance With Somebody" was every A-lister's anthem as Modern Family stars Sarah Hyland and Nolan Gould danced in a circle while lip synching along. Aduba and her OITNB costars also had an absolute ball to the 1987 classic.
And if you don't take selfies, did it even really happen? Well Mad Men stars Christina Hendricks, January Jones and Kiernan Shipka all got together to take a photo at their booth as nearby Anna Chlumsky and Julia Louis Dreyfus took a Veep selfie together.
Sofia Vergara and husband Joe Manganiello, who made their first red carpet appearance as a married couple, got photobombed by her Modern Family costar Eric Stonestreet.
DiCaprio made a quick stop as he was swarmed by well wishers who congratulated him on his best actor win.
Spotlight's award-winning ensemble had so many trophies at their booth that Liev Schreiber almost took the wrong SAG award off the table before longtime love Naomi Watts had to swoop in for the right one.
Over at the Netflix/Weinstein after-party, Tremblay had a milkshake from In-N-Out in hand! Jacob and his dad Jason went up to the DJ and requested songs. We're keeping our fingers crossed for another "Uptown Funk" video on social media soon!
Reporting by PATRICK GOMEZ, MELODY CHIU, ELIZABETH LEONARD, MIA McNIECE & GERILYN MANAGO