Joel was born in 1967 near Rochester, New York to agnostic parents who became born-again Christians when he was a child. At the age of 17, he became a born-again Christian and now identifies as a Jewish believer in Jesus. After graduating in 1988 from Syracuse University, he worked for Rush Limbaugh as a research assistant. Later he worked for U.S. Presidential candidate Steve Forbes as a campaign advisor. Rosenberg opened a political consultancy business, which he ran until 2000, advising former Israeli Deputy Prime Minister Natan Sharansky and then-former Prime Minister Benjamin Netanyahu where he garnered much of his information on the Middle East that he would later use in his books.

Following Netanyahu's loss in 1999, Joel decided to retire from politics altogether and begin a new career in writing. His first book, The Last Jihad, was the first of a five-part fictional series involving terrorism and how it may relate to Bible Prophecy. The book was written nine months before the September 11th attacks, (a revised edition takes the event into account) and was published in 2002. When published, The Last Jihad spent 11 weeks on the New York Times best-seller list, reaching as high as number seven. It also appeared on the USA Today and Publishers Weekly best-seller lists, and hit number four on the Wall Street Journal list. The book was followed by The Last Days, which spent four weeks on the New York Times Best Seller List, hit number five on the Denver Post list, and hit number eight on the Dallas Morning News list. Following the successes of his first two novels, The Ezekiel Option was published in 2005, The Copper Scroll in 2006, and the final book, Dead Heat in 2008.

Rosenberg also wrote a non-fictional account of current events and Bible Prophecy in the book Epicenter. It was published in September 2006 and an accompanying DVD was produced in the summer of 2007. His second non-fiction book, Inside the Revolution, which talked about the different sects of Islam in the Middle East and how a significant amount of moderate Muslims are coming to Christianity in the region was released in 2009 and also made it onto the New York Times best-seller list, reaching as high as #7 as of 27 March 2009.

Rosenberg's novels have attracted those interested in Bible Prophecy, due to several of his fictional elements of his books that would occur after his writing of books. Nine months before the September 11th attacks, Rosenberg wrote a novel with a kamikaze plane attack on an American city. Five months before the 2003 invasion of Iraq, he wrote a novel about war with Saddam Hussein, the death of Yasser Arafat eight months before it occurred, a story with Russia, Iran, and Libya forming a military alliance against Israel occurring the date of publishing, the rebuilding of the city of Babylon, Iran vowing to have Israel "wiped off the face of the map forever" five months before Iranian President Ahmadinejad used similar language, and the discovery of huge amounths of oil and natural gas in Israel (a major gas discovery occurred in January 2009). A brief article in U.S. News & World Report referred to him as a "Modern Nostradamus," although Rosenberg tries to play down those proclamations, stating that "I am not a clairvoyant, a psychic, or a 'Modern Nostradamus,' as some have suggested." He gives the credit for his accurate predictions to studying Biblical prophecy and applying to the modern world.

Rosenberg is the founder and President of The Joshua Fund, a 501 not-for-profit charity that seeks to "Bless Israel and her neighbors in the name of Jesus, according to Genesis 12:1-3". The fund has raised $1.2 million in 2008 alone and dedicated the money to those afflicted by war and terrorism, specifically those in Israel, the Palestinian Territories, and Lebanon.

Rosenberg has been interviewed on radio and TV programs about his views on the End times, and Israeli politics, including ABC's Nightline, CBN's The 700 Club, CNN Headline News, Fox News Channel, MSNBC, The Rush Limbaugh Show, The Glenn Beck Program, History Channel, and The Sean Hannity Show. He has been profiled twice by The New York Times, and was the subject of two cover stories in World magazine.

He has also spoken at universities, churches, political events, bookseller conventions, fund-raisers, the International Spy Museum, to members of the US Congress, the White House, CIA, and The Pentagon.

Media Matters for America criticized Rosenberg's July 31, 2006, Paula Zahn Now appearance that "featured a segment on 'whether the crisis in the Middle East is actually a prelude to the end of the world,' marking the third time in eight days that CNN has devoted airtime to those claiming that the ongoing Mideast violence signals the coming of the Apocalypse." It featured Rosenberg comparing apocalyptic Scripture in the Bible to modern events, which he views through what he calls the "third lens of scripture."

Rosenberg's views on the War of Ezekiel 38—39 involving Gog and Magog conform to the 19th century eschatology that originated with dispensationalism and therefore are not universally accepted in the Christian community. Partial preterist Gary DeMar has debated Rosenberg on this subject. Rosenberg's work and responses to it by world leaders has earlier precedents in the work of Herbert Armstrong and the Worldwide Church of God (WCG), especially its Plain Truth magazine until 1995, when changes in the WCG's doctrines led its leaders to disavow further speculation and overemphasis in Bible prophecy following Armstrong's death in 1986.