According to IMDbJurnee Smollett only appeared in 14 episodes of Full House and her first appearance was at the end of the season 5 episode “Girls Will Be Boys”. After Michelle thinks Teddy (Taj Mowry) only wants to play with boys and then can’t act like a boy herself, she meets Denise at a taping of Joey’s “Ranger Joe” show. Denise’s friendship with Michelle officially begins at the end of The Long Goodbye, after she is transferred to Michelle’s class and helps Michelle get through Teddy’s move to Texas. During her time on the show, Denise proved to be a great friend to Michelle – although they did fall out on Be Your Best Friend, it was quickly resolved – and someone she could rely on for support and fun.
Smollett’s last episode was in the season 7 finale “A House Divided”, in which Denise and Teddy help Michelle keep their family in the same house after they decide to separate. The trio’s efforts are successful, but despite Denise’s involvement in it, she is quietly kicked out of the show – Teddy leaves a season later – and Michelle has a new group of friends. After this episode, Denise is not mentioned and it is only speculation if she went to a new school or moved from San Francisco.