She has black hair and is dressed in a purple matchbox dress with matching sleeveless pantalettes with purple high heels and wears a pearl necklace. She is an orange sea sponge with light brown pores and light blue eyes.
Her and her husband come to pick up SpongeBob after nematodes ate his pineapple house. In this episode, when SpongeBob is in his parents' boatmobile, he says "Goodbye Bikini Bottom!," which indicates that his parents do not live in Bikini Bottom.
Harold and Margaret are seen in a photo hung on SpongeBob's wall. When Patrick blasts his song "I Wrote This," the photo comes to life and Harold swipes the photograph of him and his wife behind the wall out of disapproval for the song.
She and her husband attend their son's birthday party.
The Q&A section of the official SpongeBob SquarePants website for New Zealand states that her name is "Claire Gretchen SquarePants." This however, is false.
In the end credits, she is listed as "Mom" and sometimes "Mrs. SquarePants."
In the episode "Sailor Mouth," after SpongeBob uses a swear word imprinted on the dumpster graffiti, the garbage man asks if he kisses his mother with that mouth, to which SpongeBob replies that he sometimes does but has not recently.