Danny McNulty is one of two actors who portrayed Harley Keiner.
- The other actor who played Harley Keiner, Kenny Johnston, was only in one episode (Wrong Side of the Tracks).
- McNulty revealed in October 2014 that he was bipolar and had a breakdown during the middle of the episode, thus the reason for Johnston replacing him as Harley Keiner. However, Johnston held the role for one episode, and the episode after that had Keiner being written out the show stating that he gone to reformatory school.
- After McNulty's disorder was improved, he reprised his role as Harley for the one last appearance on BMW, where his character had escaped from reformatory school.
- He reprised his role as Harley Keiner on the 2014 spinoff Girl Meets World.