When Donna says "You're sweating more than Nixon", she is referring to the 1960 Nixon-Kennedy television debates.
Sean Cahill, played by Neal McDonough, makes reference to another show about lawyers, Franklin & Bash (2011).
Donna and Louis do a Shakespeare play. Louis middle name is Marlowe which is the name of a contemporary of Shakespeare Christopher Marlowe who some think wrote many of Shakespeare's plays.
Brendan Hines (Logan Sanders) and Rick Hoffman (Louis Litt) have previously worked together on Lie to Me (2009).
D.B. Woodside and Gina Torres, who play lovers on this show, also played lovers in another TV series, 24 (2001).