Silverstein's editor at Harper & Row, Ursula Nordstrom, encouraged Silverstein to write children's poetry. Silverstein said that he had never studied the poetry of others and had therefore developed his own quirky style, laid back and conversational, occasionally employing profanity and slang. In a 1975 Publishers Weekly interview, he was asked how he came to do children's books:
Silverstein's "The Ballad of Lucy Jordan", first recorded by Dr. Hook in 1975, was re-recorded by Marianne Faithfull (1979), Belinda Carlisle (1996), and Bobby Bare (2005) and later featured in the films Montenegro and Thelma & Louise. "Queen of the Silver Dollar" was first recorded by Dr. Hook on their 1972 album Sloppy Seconds, and later by Doyle Holly (on his 1973 album Doyle Holly), Barbi Benton (on her 1974 album Barbi Doll), Emmylou Harris (on her 1975 album Pieces of the Sky) and Dave & Sugar (on their 1976 album Dave & Sugar).
He had one daughter, Shoshanna Jordan Hastings, born June 30, 1970, with Susan Taylor Hastings of Sausalito, California, whom he reportedly met at the Playboy Mansion. Susan died on June 29, 1975, one day before Shoshanna's fifth birthday, and Shoshanna went to live with her uncle and aunt in their Baltimore home. Shoshanna died April 24, 1982, at age 11, of a cerebral aneurysm. The book A Light in the Attic is dedicated to her.