In a statement posted to Instagram, Harrison said he is "deeply remorseful" and apologized to "the Black community, to the BIPOC community."
"This historic season of 'The Bachelor' should not be marred or overshadowed by my mistakes," the statement read.
It is unclear if or when he will return to the show franchise.
The apology refers to contestant Rachael Kirkconnell, who was reportedly photographed at an antebellum plantation-themed fraternity formal in 2018. Kirkconnell first found herself in hot water after a TikTok went viral, claiming to show her liking posts with the Confederate flag and even sharing QAnon conspiracy theories.
Earlier this week Harrison told "Extra" correspondent and former star of "The Bachelorette," Rachel Lindsay, that the pictures were a long time ago and spoke out against cancel culture.
"Well, Rachel, is it a good look in 2018, or is it not a good look in 2021? Because there's a big difference," Harrison said during the interview.
In response, Lindsay said "It's not a good look ever. Because she's celebrating the Old South. If I went to that party, what would I represent at that party?"
Harrison apologized Thursday.
Lindsay said Harrison's comments show "the work isn't done."
"You have the face, the spokesperson of that franchise say the things that were said this week," she said.
CNN contributed to this report.
Correction: A previous version of this report proported that Harrison "stepped down" from his role. In his statement, Harrison said he has stepped "aside."