The 14-year-old actor also urges his fans to seek help if they feel pressured or bullied.
Grazer took to Instagram Sunday afternoon to apologize for the mishap and "clear up some past mistakes" for his 2.1 million followers.
"It was a dumb thing that I did due to peer pressure at school," the 14-year-old said in the video. "And I've now realized that vaping and smoking pot -- it's stupid and it's not cool and it's not worth it."
Grazer -- who also starred in CBS' "Me, Myself, & I," which was cancelled after just six episodes -- paused to look down at his notes before continuing. "I've learned my lesson, and I've learned it the hard way. Please don't make the same mistakes that I did. If you feel peer pressured or bullied, get help."
Grazer then thanked his fans for the "continued love and support."
While the video was up on his page on Monday morning, it had been removed by midday. Watch it below via PopCrave.
Jack Dylan Grazer responds to backlash over smoking video: "It was a dumb thing that I did due to peer pressure at school. And I’ve now realized that vaping and smoking pot, it’s stupid." pic.twitter.com/VAvtLfngFN— Pop Crave (@PopCrave) January 21, 2018
The video in question shows Grazer puffing on a blunt while his friends cheer him on. "Good job, good job," they're heard saying in the video below.
One of the kids is also heard saying, "If my parents found this, they would kill me."
So, uh, why capture it on video then? At least they weren't eating Tide pods.
Jack Dylan Grazer, the 14 year-old star from the 2017 'It' movie, is currently under fire due to a leaked video of him smoking weed. pic.twitter.com/pRRAlO1bYw— Pop Crave (@PopCrave) January 21, 2018