TMZ even obtained photos of the baby passed out, sleeping in her car seat well after midnight while music blared and drunk partygoers stumbled by.
But Grammer, 57, has a perfectly rational explanation for why he took his daughter to one of the year's craziest parties -- he couldn't find a good babysitter.
The actor released a statement explaining why baby Faith accompanied him and his wife Kayte, 31, to the Halloween rager:
"Kayte is breast-feeding and we do not have a nanny or a trusted baby-sitter at this time, so Faith goes everywhere with us. The baby slept as her ears were covered the entire time and we left shortly after midnight," the actor exlained.
The actor's claims contradict TMZ's initial reports that Grammer and his wife partied until "the wee hours of the morning," and he added:
"We enjoyed the evening. We love our child. Kayte is my wife and lady love. We love our child. Kayte is my wife and lady love ... The world is round. All our eyes are blue. Happy Halloween and Cock-a-doodle-doo!"
Kelsey Grammer wasn't the only star to hit up a Halloween party this past weekend. Check out more stars in costumes:
Katy Perry as Jane Lane and Shannon Woodward as Daria.
"HAPPY HALLOWEEN!! Me and Mariska starting the night!! #boo," the "Smash" star tweeted Wednesday.
Darren Criss is a boy scout and probably a big fan of "Moonrise Kingdom."
We never thought we'd say it, but the "Jersey Shore" star and her fiancé positively geeked it out.
No sleight of hand here. Christina Milian is the Queen of Hearts.
George Clooney's girlfriend is "Black Swan."
Pop starlet Miley Cyrus' mum and sister Tish Cyrus and Brandi Cyrus are all dressed up for Halloween as they head to the Roosevelt hotel for a party in Hollywood.
Jeremy Piven as Che Guevara at the Playboy Mansion Halloween Party in Beverly Hills, California on October 27th, 2012.
Sacha Baron Cohen donned a bizarre monkey-cow costume.
P. Diddy rocked out at the Playboy Mansion Halloween Party in Beverly Hills, California on October 27th, 2012.
Brandon Davis at the Playboy Mansion Halloween Party in Beverly Hills, California on October 27th, 2012.
One Direction singer Liam Payne does his best Batman in London.
Lucy Hale as a unicorn.
In this Image released by Mattel, actress Shenae Grimes, from the series "90210", left, has a fitting of her Monster High Frankie Stein Halloween costume created by "Project Runway" alum Chris March, Wednesday, Oct. 17, 2012, in El Segundo, Calif. Grimes will be attending "Glee" cast member Matthew Morrison's 3rd Annual Halloween Bash, dressed as Frankie Stein, daughter of Frankenstein, from the popular Monster High franchise. This year, the popular Halloween party will be sponsored by Monster High. (AP Photo/Mattel, Rene Macura)
Heidi Klum gets fitted for her 13th annual Halloween party at finale sponsored by HobNob Wines, Svedka Vodka And Smartwater on September 3, 2012 in New York City.
Sarah Hyland as Spinelli from "Recess."
Actress/model Stacy Keibler arrives at Hyde Bellagio at the Bellagio to host a Halloween masquerade party on October 27, 2012 in Las Vegas, Nevada.
Kim Kardashian attends 2nd Annual Midori Green Halloween Party at Avenue on October 27, 2012 in New York City dressed as a mermaid.
Nicole Scherzinger as a vampire.
Kim Kardashian as a leopard.
Holly Madison as Sleeping Beauty.
Fergie as Lindsay Lohan.
Christina Milian as Sulley.
Fergie & Josh Duhamel as Angelyne & Dennis Woodruff.
Christina Aguilera as ???
Paris Hilton as Alice.
Kris Jenner as Wonder Woman.
Ashley Benson as Tweedle Dee (or Dumb).
Hugh Hefner as a vampire.
Holly Madison as the Cheshire Cat.
Hilary Duff in a Día de los Muertos costume.
Kim Kardashian as Kris Jenner.
Fergie as a sexy cat.
Bonnie & Clyde
Julie Bowen as a scary Bo Peep.
Genevieve Jones & Nicky Hilton as a KISS member and a leopard.
Adam Lambert as a vampire.
Bella Thorne as a vampire bride.
Liam Payne as Batman.
Shanae Grimes as a skeleton.
Scott Disick as Patrick Bateman.
Nicole Richie and friends as Wilderness Girls from "Troop Beverly Hill."