Born and raised a Roman Catholic, Williams is a descendant of a family of Irish coal miners in Scranton, Pennsylvania.^[1] Williams received a Bachelor of Arts degree in English from Wilkes University, a Master of Divinity degree from Drew University, and a Doctor of Philosophy degree also from Drew. His dissertation, based on Latin texts, was on the moral philosophy of Peter Abelard.

He began his career by writing articles on Catholicism for National Review and serving as the senior editor for The Fellowship of Catholic Scholars.^{[citation needed]}

His first book, Everything You Always Wanted To Know about the Catholic Church But Were Afraid to Ask for Fear of Excommunication was published by Doubleday in 1989. The Vatican Exposed, published in 2003, became the subject of a documentary for the Discovery Channel. In The Day of Islam: The Annihilation of America and the Western World (Prometheus Books, 2007), he expands on the "American Hiroshima" scenario he believes to be imminent, in which simultaneous nuclear attacks on seven to ten American cities would create havoc in American society. Operation Gladio: The Unholy Alliance between the Vatican, the CIA, and the Mafia, published in 2014, was optioned for background information for a possible mini-series for American Movie Classics.^{[citation needed]} that was never developed. His most recent work, Among the Ruins: The Decline and Fall of the Roman Catholic Church, was published in 2017.

Williams is the only journalist to capture three first-place Keystone Press Awards in three different categories in the same year.^{[citation needed]}

In Williams' 2006 book Dunces of Doomsday, he claimed that Adnan Shukrijumah, Amer el-Maati, Jaber A. Elbaneh and Anas al-Liby had all been seen around Hamilton, Ontario the previous year, and that Shukrijumah had been seen at McMaster University where he "wasted no time in gaining access to the nuclear reactor and stealing more than 180 pounds of nuclear material for the creation of radiological bombs". He was subsequently sued by the university for libel, with the lawyer representing the university in the case saying that, "Mr. Williams' allegations about McMaster [are] on a par with UFO reports and JFK conspiracy theories.... The notion that because there are people on faculty from Egypt that McMaster is then a haven for terrorism is not only logically offensive, it smacks of racism."^[2] The publisher later apologized for allowing Williams to print statements which "were without basis in fact";^{[3][page needed][4][a]} Williams remained defiant saying, "I love them coming after us. At the end of the day these people are going to be bloodied because what I am saying is true. They are not going to walk away from this unscathed because I will proclaim what is going on at McMaster from the rooftops."^[2]

In 2010, he was quoted as saying he had become "a pariah in the publishing world";^[5] however, he remains a popular speaker on the Christian circuit.^{[citation needed]}

• Everything You Wanted to know about the Catholic Church - Doubleday Books, ISBN 0-385-24882-2 (1989)
• The Complete Idiot's Guide to the Crusades, Penguin, ISBN 0-02-864243-0 (2001)
• The Complete Idiot's Guide to the Lives of the Saints, Penguin, ISBN 0028642112 (2001)
• The Life and Work of Mother Teresa, Alpha, ISBN 0-02-864278-3 (2001)
• Al Qaeda: Brotherhood of Terror - Alpha Books ISBN 0-02-864352-6 (2002)
• The Vatican Exposed. Money, Murder, and the Mafia - Prometheus Books ISBN 1-59102-065-4 (2003)
• Osama's Revenge: The Next 9/11: What the Media and the Government Haven't Told You, Prometheus Books, ISBN 1-59102-252-5 (2004)
• Al Qaeda Connection: International Terrorism, Organized Crime, and the Coming Apocalypse, Prometheus Books, ISBN 1-59102-349-1 (2005)
• Dunces of Doomsday: 10 Blunders that Gave Rise to Radical Islam, Terrorist Regimes, and an American Hiroshima, WND Books, ISBN 1-58182-529-3 (2006)
• The Day of Islam: The Annihilation of America and the Western World, Prometheus Books, ISBN 1-59102-508-7 (5 June 2007)
• Operation Gladio: The Unholy Alliance between the Vatican, the CIA, and the Mafia, Prometheus Books, ISBN 978-1-61614-974-1 (2015)^[6]
• Among the Ruins: The Decline and Fall of the Roman Catholic Church (2017)