Like Father, Like Clown is the fifth episode of Season 3. Jay Kogen and Wallace Wolodarsky agreed to parody the 1927 movie The Jazz Singer and establish that Krusty is Jewish.
Krusty finally drops by to have dinner with the Simpsons to thank Bart for saving him from jail (see "Krusty Gets Busted"), and drops a bombshell: His real name is Herschel Krustofsky, and he is estranged from his rabbi father, who disowned him when Krusty chose to be a clown instead of a rabbi. Now, Bart vows to reunite Clown and Rabbi.
After finishing his show, Krusty decides to free himself up for the night and cancels all his plans, including a thank-you dinner with Bart. Krusty is reminded of how Bart saved him from prison, but still cancels and not for the first time. This makes Bart extremely upset even to the point of turning in his membership badge. He sends a letter to Krusty and after his secretary reads it, she is very disappointed and forces Krusty to go. Marge tells Bart that Krusty is coming and he instantly cheers up.
At dinner, the Simpsons ask Krusty to say grace and he starts to recite a prayer in Hebrew. Realizing that Krusty is Jewish, Lisa speaks of his heritage, making Krusty break down in tears. After some convincing from the family to why he is so depressed about it, Krusty tells the family his real name, Herschel Krustofsky, and describes his upbringing in the Lower East Side of Springfield. His father was a rabbi and he wanted Krusty to be a rabbi as well, but Krusty wanted to be a clown. One night Krusty got a chance to perform at a rabbi's convention but he was sprayed by seltzer, his make-up fell off and his father recognized him and disowned him. After the story is over, Krusty becomes very emotional. He ends up outstaying his welcome at the Simpsons, not leaving until after 1am. He finally leaves and tries calling his dad, but is afraid that his dad will reject him again, so he doesn't say anything.
Bart and Lisa notice him getting increasingly depressed (even to the point of crying during his TV show) so they agree to try to locate and reunite Krusty with his father. They find him in a radio studio where a framed "Larry Davis Experience" gold record hangs on the wall. Krusty's father is still mad at him, so after several tries, they finally convince Hyman to forgive Krusty by saying a quote from Sammy Davis, Jr., a Jewish entertainer just like Krusty, in which the entertainer makes a passionate speech about the struggles that the Jewish people have overcome. This finally convinces Rabbi Krustofsky that entertainers have a place in Jewish heritage. Bart, Lisa, and the now proud father meet Krusty on the set of his show, where they reconcile their differences together.
Krusty the Clown Show Characters, Locations and Key Episodes