Brooks, who has been on tour this year with his 2016 album Gunslinger, was presented his entertainer of the year award by country music legend Reba McEntire.
Garth admitted he did lip-synch, saying that he was considering using a track for his performance before the show.
"Right now we're in the middle of 12 shows in 10 days", he told Fox News "We've got four days (where) we're doing two shows a day. Not 10 shows in 12 days, 12 shows in 10 days", he told reporters. "We did a game-time call on whether to sing the track or lip-sync, and chose to lip-sync".
"My voice just isn't going anywhere, and we wanted to represent country music the best we can", Brooks said.
The "Friends in Low Places" singer was dubbed entertainer of the year - for the second consecutive year and for the sixth time overall - Wednesday during country music's biggest night. Read some of the strongest reactions below.
"My heart is broken - how could you lip sync?" one fan wrote.
"Getting this presented to me by the entertainer of a lifetime, I thank you", Brooks said. "I'm so happy, happy for the band and crew".
You can see the performance for yourself in these clips from the CMAs. I was talking to Kelsea (Ballerini) backstage about how we get to do this for a living.
ABC/Image Group LA If the 51st Annual CMA Awards seemed a little like church, the backstage press room seemed a lot like a confessional.
The 55-year-old belted out Ask Me How I Know, before he picked up the award of the night for entertainer of the year.