Gardner is best known for his 1962 play "A Thousand Clowns," which ran for 428 performances. He received an Oscar nomination for the screenplay for the successful 1965 movie adaptation. The play was revived in 1996 and 2001. Both the 1962 play and the movie starred Jason Robards, Jr. as Murray Burns, a charming, unemployed children's show writer, who is forced to choose between social conformity and the probable loss of custody of his 11-year-old nephew to the Child Welfare Bureau. The Robards character was in part based on Gardner's friend at that time, humorist Jean Shepherd. In 2000, Robards wrote: I feel "A Thousand Clowns" is his masterpiece. It is a real human comedy of poignancy and laughter, with all of humanity's foibles and eccentricities. There is a great depth of love and understanding for all in this play. There are great life lessons to learn daily, which I find myself still doing. For Herb Gardner to have written this play in his early twenties is a miracle.