Quarterback for Oakwood High School, a bitter football rival of Lawndale High. Brittany dated him briefly, an affair discovered by Upchuck and used against Brittany in "The Lab Brat."
In 2000, the MTV tie-in websites (transcribed here) list Theodore Wozniak as the Oakwood Taproots quarterback. Was Sam replaced or did he graduate?
Sam Stack in Fanfic
Sam made his first known appearance in "Ring Toss" as Sam Stagg and Kristen Bealer posted a theory about Sam being related to Mr. O'Neill (either as a nephew or a secret son) but otherwise wasn't touched on much other than in his forementioned role in "The Lab Brat." On July 2012 however Shiva started an Iron Chef about Sam, there was some discussion about the character and some contributions.
Shiva's "A Lift" shows Sam helping Jane with some car trouble (and mentions that O'Neill is his Uncle), while "Last Night of Bliss For A QB" slashes him with Tommy Sherman, and finally "What Sam Really Likes" has Sam Stack hooking up with Andrea.
OverlordMikey's "A Wish for the Perfect Night" showed him as a smart jock but hopelessly in love with Brittany.