In the comics, she is the homeroom teacher at Riverdale High School, occasionally teaching English and math as well. In Jackpot Comics no.4, she is referred to as "Mrs. Grundy, the principal", but this is not correct. Her name is derived from Mrs Grundy, a name that has been used to refer to a prudish woman since the early nineteenth century. Before she became a teacher, she worked at a pickle-packing plant. During World War II, she served with the WACs, outranking Mr. Weatherbee. Despite occasional grumblings from her students, they seem to genuinely like and admire her. She, in return, tends to drive them hard, pushing Archie Andrews and Moose Mason in particular, but remains quite fond of her students.
Her first name is most often given as Geraldine. However, at least once, another staff member called her "Amanda". She was also called "Alice" in at least one mainstream story. In Archie's Double Digest (#41), she was revealed to be an alumna herself of Riverdale High School, and had run for class president, in a joke about the need to clean off the bulletin board. Her forename was given as "Elizabeth" in The Archie and Sabrina Hour, and as "Doris" in the animated series Archie's Weird Mysteries. In an earlier Archie book that listed the names of the characters, her name was also "Gertrude". Nevertheless, Geraldine remains her commonly accepted name.
In older stories, she was bald and wore a white wig, which fell off frequently, embarrassing her greatly. However, this has not been referenced for a long time and it can be assumed that this idea has been retired and that she has real hair now. Ever since her introduction, her nose has been identical in appearance to Jughead Jones' nose, and her figure just as slim as his. In one comic strip, Jughead is ordered to try on a wedding dress meant for Miss Grundy since their figures look alike. She is one of the few females that Jughead likes outside of his family.
In Life with Archie's current dramatic storylines, Miss Grundy realized how much she loved Mr. Weatherbee, and the two finally married. However, in this alternative future, she died from kidney disease not long afterward, leaving Weatherbee a broken-hearted widower.