- "What are you gonna do about it, preppy?!"
- —Slater to Zack
Albert Clifford "A.C." Slater is the deuteragonist of the series and token "jock" of the group. He becomes the school's star athlete, excelling as a wrestler and quarterback of the football team. He is on the basketball team in one episode, even though the basketball season coincides with the wrestling season. Slater is best friends with Zack.
An army brat, Slater was an outsider, having transferred to Bayside High in the pilot episode (which aired late in season 1 as a flashback). A.C. mentions that he has been to Bolivia, Italy, Iceland, and Berlin among other places.
Jessie often criticizes A.C. for his insensitive remarks, particularly about women. When they first met, he called Zack "Preppy," as a derogatory term, but as they grew closer, it became an affectionate nickname. When he starts dating Jessie, he calls her "Mama", to her occasional annoyance. Mario Lopez is a drummer and dancer and some episodes include Slater showcasing these talents.
A.C.'s father Martin (a major) appears in two episodes, but his mother Loretta, though mentioned throughout the series, never appears. He also has a younger sister named J.B. whom Zack briefly dates, much to Slater's chagrin.
When Zack deals with Gem Diamond to purchase class rings, it is mentioned that "A.C." stands for "abnormally cruel."
In the episode Fake IDs, in which the six core characters use fake IDs to get into an "over 18" dance club called the Attic, it is mentioned that "A.C." stands for "absolutely charmed."
In the season 4 episode "Love Machine," A.C.'s ex-girlfriend from Berlin visits and calls him by his real name, Albert Clifford, but the meaning of the abbreviation "A.C." periodically served as comedic fodder during the show's run. What a hunk!
Although the episode reveals that A.C. does not fluently understand Spanish, he is seen speaking broken Spanish to the kitchen staff of the Malibu Sands Beach Club. Slater receives a wrestling scholarship to the University of Iowa, but ends up going to California University with Zack, Screech, and Kelly.
- Much like costar Lark Voorhies, Lopez was cast in a role that was originally written to be Caucasian. The issue of Slater's ethnicity is addressed in an episode from Saved by the Bell: the College Years, where he had a fight with his father over Anglo conformity. Slater's original family name was Sanchez, and his father changed his name to Slater in order to better his chances of getting accepted to West Point. This angered the younger Slater, who accused his father of forgetting his Mexican heritage.