"I regret it every day, but it was the right decision for my family and for me. And I plan on staying deeply involved," Biden said in an interview with Connecticut NBC affiliate WVIT.
Biden said the Democratic race between former Secretary of State Hillary Clinton and Vermont Sen. Bernie Sanders is "what I expected," adding that there has been a "real robust debate between Hillary and Bernie, as there would have been if I had gotten in the race."
Biden's comments came during a spate of local television interviews in which he pushed President Barack Obama's executive actions on gun control.
Biden ended months of intense speculation about his political future in October with a sudden announcement that he wouldn't seek the presidency, abandoning a dream he's harbored for decades.
With his wife, Jill, and Obama at his side in the White House Rose Garden, Biden said the window for a successful campaign had closed, noting his family's grief following the death of his son, Beau.
"While I will not be a candidate, I will not be silent," he said on October 21 in a speech that highlighted Democratic themes on income inequality along with a call for a national movement to cure cancer. "I intend to speak out clearly and forcefully, to influence as much as I can where we stand as a party and where we need to go as a nation."
The question of whether Biden, 72, would enter the race had consumed Democrats for months