Tara Strong reprises her role as Harley Quinn. For a majority of the game she is playing Dr. Harleen Francess Quinzel, the Joker's psychiatrist at Arkham Asylum.
Oswald Chesterfield Cobblepot/The Penguin's ship, The Final Offer, was previously a cargo ship/cruise liner named The Olivia B. Meredith. A tribute to Burgess Meredith (born Oliver Burgess Meredith) the actor who portrayed the Penguin in Batman e Robin (1966).
This is the first video game in the Batman: Arkham series that does not feature the vocal talents of fan favorites Kevin Conroy and Mark Hamill in the roles of Bruce Wayne/Batman and The Joker, respectively.
When Batman first learns of the assassins, he states that Copperhead's file refers to a man, however, she is a woman. This is a nod to the character being a male in the comics, but a female in the game.
Batman: Arkham Origins was not included in the Batman: Return to Arkham (2016) remaster collection. The official reason is Warner Bros. wanted the collection to focus on Rocksteady's groundbreaking titles. Fans have theorized though that the real reasons are probably because the game was the fan least favorite and was too buggy, thus not justifying the extra effort. Even with Origins being upheld as the fan least favorite, many fans were disappointed that it wasn't included since it makes the "collection" incomplete.