Barstool Sports honcho Dave Portnoy is apologizing for his past on-camera usage of the n-word ... and he's now vowing to do better going forward.
"I should have had [my employees'] back from the beginning and been like, 'Yup, I wish I didn't f**king say that sh*t,'" Portnoy said in a video Thursday. "I'm sorry I said it. I'm sorry it offended people."
Clips from around four years ago surfaced of Portnoy this past week ... showing the Barstool Sports founder saying and rapping the n-word on company-produced content videos.
In another one of the resurfaced clips, Portnoy also made insensitive comments about Colin Kaepernick ... saying the 49ers QB looked like an "ISIS guy," and adding, "throw a head wrap on this guy and he's a terrorist."
The unearthed footage was immediately met with backlash ... with critics calling for sponsors to drop partnerships with Barstool ASAP.
Initially, Portnoy defended the remarks ... saying he was "uncancellable." But after he says he spoke with his employees, the 43-year-old decided to issue a mea culpa.
"I can't apologize for my existence, but I can be better," Portnoy said. "And, I'm going to be better for [my employees]."
Portnoy says he'll lean on the diversity of his staff to make sure situations don't arise like this again in the future ... adding, "To all the guys that work for me, I want you to know I have your back."
"And, I want this to be a place that you f**king can be proud of and if you're not this second, we'll get there. We'll f**king get there."