Jonathan Coulton himself makes a cameo appearance in the next season story The Line (2014). He also provided musical recaps for BrainDead (2016), created by the same people.
Anne Stevens, played by Talia Balsam, previously appeared in episode 5.3, A Precious Commodity (2013).
Chris Noth (Peter Florrick) & Peter Bogdanovich (Himself) also worked together on episode 6.20, Bombshell (2007), of Law & Order: Criminal Intent (2001), as Mike Logan & George Merrit respectively.
Matthew Lillard and F. Murray Abraham have previously starred in the horror film - Thir13en Ghosts (2001).
Chris Noth (Peter Florrick) & Charles Malik Whitfield (Rebel Kane) also worked together on two episodes of Law & Order (1990), as Mike Logan & Babatunde's Roommate/Smith respectively.