The 2008 presidential candidate was indicted last month on charges that he used political funds in order to cover up his affair scandal and secret love child.
While Edwards later pleaded not guilty and insisted that he did not break the law, a Federal Election Committee ruled unanimously on Thursday that the politician must pay the US Treasury all of the funds in question.
"There is no question that I've done wrong. I take full responsibility for having done wrong," he told reporters following the indictment. "I will regret for the rest of my life the pain and the harm that I've caused to others. But I did not break the law, and I never, ever thought I was breaking the law."
People reports that the $2.3 million may come from the remaining $2.6 million (£1.6m) left in Edwards's campaign account and does not need to be from his personal account.
Edwards admitted to fathering a 2-year-old daughter with former mistress Rielle Hunter in January 2010, prompting his split from his former wife, the late Elizabeth Edwards.