Both his book and the film are rife with controversial assertions. “How, for example, did Obama get elected as a complete unknown?” Mr. D’Souza asks in the book. “There is a one-word answer: slavery. America’s national guilt over slavery continues to benefit Obama, who ironically is not himself descended from slaves.”

Newt Gingrich, former speaker of the House and co-host of CNN’s “Crossfire,” says Mr. D’Souza’s roots and scholarly bona fides give him “credibility” in right-wing circles. “A lot of conservatives feel comfortable being told things by Dinesh that they might not exactly feel comfortable being told by someone else,” he said.

After Dartmouth, Mr. D’Souza worked at the Policy Review, a conservative journal in Washington, before joining the Reagan administration in 1988 as an adviser. His first book, “Illiberal Education,” published in 1991, was at the center of a debate over so-called political correctness on America’s college campuses.

Since then, however, Mr. D’Souza’s career has taken a series of unexpected turns. His views have drawn criticism not only from the left but also from the right. His 2007 book, “The Enemy at Home: The Cultural Left and Its Responsibility for 9/11,” ignited outrage among some conservatives, who considered its thesis — captured succinctly in the subtitle — not only deeply flawed but irresponsible. And in 2012, Mr. D’Souza abruptly resigned as president of King’s College, a Christian school in Manhattan, after it surfaced that he was involved with a woman who was not his wife.

Mr. D’Souza, 53, said his foray into filmmaking began after a talk with the billionaire Joe Ricketts, a major donor to right-wing causes. According to Mr. D’Souza, Mr. Ricketts was taken with his 2010 book, “The Roots of Obama’s Rage,” and wanted more Americans to be exposed to its thesis, which argues that Obama is carrying out the anticolonial agenda of his Kenyan father.

“A book can reach 50,000, maybe 100,000, people,” Mr. Ricketts said, as recalled by Mr. D’Souza. “How do you reach a million people?”