Gosselaar was asked to read through the script with a number of kids, and a second audition was scheduled for finalists.
It was Gosselaar himself who insisted that Dustin Diamond was right for the part as he believed Diamond was Screech in real life.
Veteran writer Sam Bobrick was brought on to write the episode and the cast included future stars Jonathan Brandis, Brian Austin Green, and Jaleel White.
Berkley originally auditioned for the role of Karen, a love-interest of Zack's on Good Morning, Miss Bliss, but lost the role because she was so much taller than Gosselaar at the time.He wanted her for the role, believing she had the perfect all-American girl appeal for the role, while others felt that Berkley, as the more experienced actress, would be a more reliable choice.Ultimately, Engel convinced the others after a read-through with Lopez, and Thiessen received the role.Primarily focusing on lighthearted comedic situations, it occasionally touches on serious social issues, such as drug use, driving under the influence, homelessness, remarriage, death, women's rights, and environmental issues.The series starred Mark-Paul Gosselaar, Dustin Diamond, Lark Voorhies, Dennis Haskins, Tiffani-Amber Thiessen, Elizabeth Berkley, and Mario Lopez.Engel particularly envisioned one character, Zack Morris, who "would be that incorrigible kid who could lie to your face, letting you know very well that he's lying, and make you love him for it all the same." Engel insisted that the show could not go on without Zack Morris, but he turned out to be one of the most difficult characters to cast.