- “His name is Danny Kessler and he's the closest any of us are ever going to get to Brad Pitt.”
- ―Lizzie's animated ego to the viewers
The show's first aired episode "Rumors" shows that Danny is one of the students at Lizzie McGuire's school Hillridge Junior High. He is introduced when Claire Miller lies to Lizzie and Miranda in the cafeteria that Danny is interested in talking to Miranda. Fooled, Miranda goes to meet him as he gets up from his table, but he feels startled to find her suddenly greeting him, and when Miranda mentions what Claire said, Danny admits that he had no idea that happened and that he is not really wanting to have a conversation with her.
In "When Moms Attack", Danny goes on a camping trip with his school, having Mr. Pettus as his and the boys' chaperone. At one point, while on a hike to search for certain species of wildlife, Danny and his group pull a prank on the girls with water pistols, before they are soon stopped by the girls' chaperone, also Lizzie's mother, Jo McGuire. Later that night, Danny and his friends get payback from the girls, just as Mr. Pettus spots only Jo in the tent, and is unaware that she is not the only one responsible for the incident.
Danny has made no more appearances in the series, but has been mentioned again in "My Fair Larry".
Danny is briefly mentioned by Lizzie while she is impersonating Isabella Parigi, saying that he noticed her wearing a similar-colored dress at her spring formal compared to the dress she chooses to wear while helping Paolo do a performance at the International Music Video Awards with Isabella out of the picture.