Theresa works at a clothing store called Junior 5, and as such does a lot of business with the Fashion Club. Not much is known about her, but it can be assumed that she is a girl of phenomenal patience. She is not above spewing a little empty flattery at the fashion club in order to get them to make purchases - presumably, Theresa works on commission. However, she won't bend the rules for them too far, refusing to take returns that were bought on sale because it's against store policy.

Quinn has Theresa follow her around catching outfits when she and Helen are planning for a Mother/Daughter Fashion Show.

During a Lawndale Lions losing streak, it falls to Theresa to explain to the Fashion Club that, as students of a Loser school, their image is suffering and they must therefore use fitting room eight (the unpopular people's dressing room).