After a stint on television (see below), he returned to radio. "Shep," as he was known, settled in at WOR radio New York City, New York on an overnight slot in 1956, where he delighted his fans by telling stories, reading poetry (especially the works of Robert W. Service), and organizing comedic listener stunts. The most famous of the last involved creating a hoax about a non-existent book, I, Libertine, by the equally non-existent 18th century author "Frederick R. Ewing", in 1956. During a discussion on how easy it was to manipulate the best seller lists, which at that time were based not only on sales but demand, Shepherd suggested that his listeners visit bookstores and ask for a copy of I, Libertine which led to booksellers attempting to purchase the book from their distributors. Fans of the show eventually took it further, planting references to the book and author so widely that demand for the book led to it being listed on The New York Times Best Seller list.Shepherd, Theodore Sturgeon and Betty Ballantine later wrote the actual book, with a cover painted by illustrator Frank Kelly Freas, published by Ballantine Books. Among his close friends in the late 1950s were Shel Silverstein and Herb Gardner. With them and actress Lois Nettleton, Shepherd performed in the revue he created, Look, Charlie. Later he was married to Nettleton for about six years.

When he was about to be released by WOR in 1956 for not being commercial, he did a commercial for Sweetheart Soap, not a sponsor, and was immediately fired. His listeners besieged WOR with complaints, and when Sweetheart offered to sponsor him he was reinstated. Eventually, he attracted more sponsors than he wanted—the commercials interrupted the flow of his monologues. Ex WOR engineer, Frank Cernese, adds: The commercials of that era were on "ETs"—phonograph records about 14" in diameter. Three large turntables were available to play them in sequence. However, Shepherd liked the engineer to look at him and listen when he told his stories. That left little time to load the turntables and cue the appropriate cuts. That's when he started complaining about "too many commercials"!. He broadcast until he left WOR in 1977. His subsequent radio work consisted of only short segments on several other stations including crosstown WCBS. His final radio gig was the Sunday night radio show "Shepherd's Pie" on WBAI-FM in the mid-1990s, which consisted of his reading his stories uncut, uninterrupted and unabridged. The show was one of WBAI's most popular of the period.

In later life he publicly dismissed his days as a radio raconteur as unimportant, focusing more on his writing and movie work. This distressed his legions of fans who fondly remembered nights with Shepherd on WOR. He once made such comments during an appearance on the Tomorrow Show with Tom Snyder. This contrasts with his frequent criticisms of television during his radio programs.

In addition to his stories, his shows also contained, among other things, humorous anecdotes and general commentaries about the human condition, observations about life in New York, accounts of vacations in Maine and travels throughout the world. Among the most striking of his programs was his account of his participation in the March on Washington in August 1963, during which Dr. Martin Luther King gave his "I Have a Dream" speech, and the program that aired on November 25, 1963—the day of President Kennedy's burial. However, his most scintillating programs remain his oftimes prophetic, bitingly humorous commentaries about ordinary life in America.

Throughout his radio career, he performed entirely without scripts. His friend and WOR colleague Barry Farber marveled at how he could talk so long with very little written down. Yet during a radio interview, Shepherd once claimed that some shows took several weeks to prepare. On most of his Fourth of July broadcasts, however, he would read one of his most enduring and popular short stories, "Ludlow Kissel and the Dago Bomb that Struck Back," about a neighborhood drunk and his disastrous fireworks escapades. In the 1960s and 1970s, his WOR show ran from 11:15 pm to midnight, later changed to 10:15 pm to 11 pm, so his "Ludlow Kissel" reading was coincidentally timed to many New Jersey and New York local town fireworks displays, which would traditionally reach their climax at 10 pm. It was possible, on one of those July 4 nights, to park one's car on a hilltop and watch several different pyrotechnic displays, accompanied by Shepherd's masterful storytelling. [Source: Wikipedia]