Courtney Lane is the daughter of Summer Lane, she and her brother Adrian, and their two unnamed siblings, take every chance to run away from their mother.
Courtney is frequently seen with her brother, Adrian. It is not known if their last name is "Lane" or if they uses their father's surname. Furthermore, it is not known where Courtney resides in the birth order of Summer's children, or if she's younger or older than Adrian; they seem to be close in age, possibly twins.
The Teachings of Don Jake reveal that Summer's children keep running away from her. When Summer's spoken or written, she seems more irritated than concerned about this.
In The Daria Diaries, two postcards from Adrian and Courtney can be found among the collection of postcards on several pages: one from Amish Country in Pennsylvania and one from the Petrified Forest, Arizona. The first included "If you hear from Mom, tell her to chill. We'll call her in a couple of weeks" and the second included: "We're saving up, and we'll probably be home for some holiday. Say hi to Mom."
Adrian and Courtney run off again in Lane Miserables, heading for Casa Lane. Summer snaps at them both times she talks to them, including accusing them of "drag[ging] me to the last place on Earth I want to be".