Carl begins to mention the only show on TV who has stars over 50, and then stops in fear of "breaking the wall". The "fourth wall" refers to an actor addressing the audience directly.
Catherine Piper's cell phone ringtone is the theme from The Practice (1997), the show from which Boston Legal is a spin-off.
Denny flashes back to a young Shirley. The vision he sees is of Shirley is Candice Bergen from the movie The Magus (1968).
Kimberly Williams-Paisley was cast to play Denny's daughter but the few scenes could not do justice to the depth need for the story. So the story line was cut. The creators liked Kimberly so much that they cast her as a lawyer in the final ever episode.