After the first song, while the leadership are discussing the situation, there is an exchange about bunnies. This is a reference to the Buffy musical Once More, with Feeling (2001), which has been named by showrunners as inspiration for Subspace Rhapsody.
The Klingon General Garkog is played by Bruce Horak, who previously recurred as the Enterprise's chief engineer, Hemmer. Uhura mentions Hemmer in her song "Keeping Us Connected" about how his belief in her changed her life before he died.
Features a cappella version of the opening theme.
Spock's "I'm the X" is the same song as Chapel's "I'm Ready" but with a different musical arrangement and lyrics (except with the first line in both songs being the same). This is a trope often used in musicals known as a "dark reprise".
Several members of the cast, such as Celia Rose Gooding (Uhura), Christina Chong (La'an), and Melissa Navia (Ortegas), have musical backgrounds that came in handy for this episode.