George Newbern (Superman), Susan Eisenberg (Wonder Woman), and Kevin Conroy (Batman) are the only actors to reprise their roles from Justice League Unlimited (2004). This would also be the final time that Kevin Conroy would work with his fellow Justice League alumni prior to his death in 2022.
In this movie, Wonder Woman carries a sword. This is the first time the DCAU Wonder Woman is seen carrying another weapon besides her Magic Lasso.
The creative team decided to specifically give Jessica Cruz a small studio apartment because they felt that most of the apartments shown on TV & movies are unrealistically large.
The scene where Superman was losing a lot of blood after getting struck by The Persuader's axe was done by Bruce Timm as revenge for not allowing him to show Superman bleed in Superman: Doomsday (2007).
The Star Boy stories where he has mental illness issues isn't mostly from the Legion of Super Heroes comics, but rather from the Justice Society comics where he goes back in time and his meds no longer work.