Herschel Shmoikel Pinkus Yerucham Krustofski (Hebrew: הרשל שמויקל פינקוס ירוחם קרסטופסקי, born c.1930s ), more commonly known as Krusty the Clown, is a fictional character on The Simpsons (His name was originally Herschel Schmoikel Krustofski, but it has changed since the episode "Today I Am a Clown". The spelling of the first and last name has been confirmed in "Bart the Fink"). He is voiced by Dan Castellaneta. Krusty is the long-time clown host of Bart and Lisa's favorite TV show. The TV show is a combination of kiddie variety-television hijinks with a sidekick, and cartoons (including the Tom and Jerry parody Itchy and Scratchy). One Krusty trademark is changing the spelling of many words that begin with C to instead begin with K, as evidenced by the original spelling of his name, Krusty the Klown, and with such events as the unfortunately-named Krusty's Komedy Klassics (KKK).

A common argument in this biography of Krusty is his age, there are many different references to his age but in the episode "Day of the Jackanapes", Krusty announces, again, the end of his entertainment career, which he says has lasted 61 years, these years added to the approximate age at which he would have started would lead people to believe he is aged around the late 70's.

The episode "Like Father, Like Clown" (based on the film The Jazz Singer), first released on October 24, 1991, expanded on his origin. According to it, he was born Herschel Schmoeckel Krustofski and is of Jewish heritage. Krusty is a third generation American. In 1902, Krusty's grandfather Zeev Krustofski left Imperial Russia for the United States and gained entry through Ellis Island.[1] His son Hyman Krustofski became an Orthodox rabbi and a leader of his community, whose wise counsel (such as if it is right to buy a Chrysler) is continually sought. Rabbi Krustofski, voiced by Jackie Mason, hoped that his son would follow in his footsteps (he brags that Herschel is at top of his Yeshiva class). However, Herschel wanted to become a clown because he wanted to make people laugh. Consequently, the Rabbi disowned him. Decades later, Krusty memorably reconciled with his father with the assistance of Bart and Lisa.