"I have learned my lesson," Kessler tweeted. "'Learned my lesson' means who knows what the next four years will bring."
The Post famously maintained a database of former President Donald Trump's falsehoods during his entire term in office. Kessler called it a "wild ride."
"We will keep doing fact checks, just not a database," he added.
In a writeup in the soon-to-be-mothballed database, the Post wrote the "Joe Biden era has offered a return to a more typical pattern when it comes to a commander in chief and his relationship with the facts — one that features frequent spin and obfuscation or exaggeration, with the occasional canard."
Kessler said the Post's section was the most "comprehensive" fact-checking outlet of Biden's presidency to date and encouraged readers to send him any Biden falsehoods his team may have missed from the first 100 days.
Critics jumped on Kessler's admission, with some calling it a clear sign of liberal bias to acknowledge it would treat a Democratic president differently.
Fox News reached out to Kessler for comment, but he did not respond.
Kessler came under fire last week for publishing a lengthy "fact check" of Republican South Carolina Sen. Tim Scott's claim of rising "from cotton to Congress," which ultimately awarded zero Pinocchios.
The Post counted 67 falsehoods from Biden in his first 100 days, chief among them his repeated, "Four-Pinocchio" claim that the new Georgia voting law limited early voting hours. Biden also compared the law to racist "Jim Crow" segregation.