In the 65 weeks since “Killing Lincoln” was released in fall 2011, Mr. O’Reilly has owned territory near the top of The New York Times’s best-seller list for hardcover nonfiction. It would have been an extraordinary run by itself, but in October he released “Killing Kennedy,” which has since sold about one million copies.

For the last full week of the year he snagged both the No. 1 and 2 spots on the list, a rare feat.

But few authors manage more than one book on the hardcover list because even regulars like the historian David McCullough and the journalist Michael Lewis do not grind it out at the pace of Mr. O’Reilly, who has produced about a book a year over the past decade and intends to keep going. Others have had two atop the paperback nonfiction best-seller list, an act most recently accomplished by President Obama, whose two memoirs “Dreams From My Father” (1995) and “The Audacity of Hope” (2006) both spiked with his election in 2008.

Of course few authors also have the television platform Mr. O’Reilly has and which he uses for 30 seconds nightly to promote his books to his nearly three million viewers.

In person Mr. O’Reilly sheds his on-air bellicosity but maintains the forward energy of a barreling freight train. During an interview, held at his corner office at Fox headquarters in Manhattan, Mr. O’Reilly barely looked up as he autographed a pile of bookplates to be put into copies to be sold on his Web site for a premium for charity. He is determined, he explained, to take advantage of the holiday season.

Thirty minutes later he pointed to the pile completed and said: “That’s about 10 grand for charity right in that pile. Not bad.” That money, he said, is likely to go to the Coalition for the Homeless, a New York-based group that has successfully sued the city and won a court-ordered “right to shelter” — just the kind of policy initiative that Mr. O’Reilly and might gleefully label “radical” or “leftist” on his program.