In the reality of Young Justice, Courtney Whitmore is the host of a popular entertainment news program called Star Girl. In the comics, Courtney Whitmore is the secret identity of the superhero Stargirl, who will be getting her own live-action series on DC Universe in August 2019. Amusingly, the character is voiced by Whitney Moore, who also hosts the Bringing Back Young Justice show about the production of Young Justice: Outsiders.
As Artemis and Halo are enjoying a day at the park in "Private Security," they are nearly run over by young man who gets a little too into the Augmented Reality game he is playing on his Goode Goggles. The episode credits identify this gamer as Henry Fyff. In the Green Arrow comics of the Rebirth era, Henry Fyff is a former Queen Industries employee whom Oliver Queen would later employ as Green Arrow's technical support, filling the role held by Felicity Smoak on Arrow.
Introduced in the episode "Away Mission," Mantis is the leader of Forager's hive and the one responsible for the idealistic young bug's exile when his attempts at forging peace between the New Gods and the bug people end in failure. In the original New Gods comics by Jack Kirby, Mantis was the leader of a hive of the bug people of New Genesis who migrated to Apokolips, finding life under Darkseid preferable to the rule of Highfather. In exchange for his loyalty, Darkseid gave Mantis phenomenal powers that made him second only to Darkseid himself. It remains to be seen if this version of Mantis will follow in the footsteps of his comic book counterpart and pledge his people to Darkseid's cause.
One of the visions Halo has of her previous life before gaining her powers involves her being harassed by a Markovian skinhead. This character is credited with the name Wilhelm Vittings, who was quite a different character in the comics but equally reprehensible. A puppet of the supervillain Psycho-Pirate, Wilhelm Vittings was one of the candidates who ran for the post of Markovia's Prime Minister as the country transitioned from an absolutely monarchy to a constitutional monarchy with a parliament. The Outsiders would later thwart Psycho-Pirate's plan to rule Markvoia by proxy and Vittings was forced from office and imprisoned.
Before beginning a training session with the rest of the Outsiders in "Evolution," Superboy listens to a sports news show hosted by a man named Steve Lombard. In the comics, Steve Lombard was a former quarterback for the Metropolis Meteors, who worked for The Daily Planet as a sports reporter. Despite his macho posturing and continual prank-playing (the most frequent target of which was the mild-mannered Clark Kent), Lombard was a noble soul, who took up writing after a career-ending knee-injury he acquired while saving a falling baby.
Casey Klebba is a security guard at STAR Labs' Detroit facility, who manages the impressive task of wounding Cheshire as she and her gang made their escape while robbing the laboratory of Dr. Silas Stone in "Triptych". He appears later in "Another Freak," as one of the STAR Labs personnel who help Dr. Stone to save his son Victor. In the comics, Casey Klebba was the chief of security at STAR Labs' Detroit facility in the 2013 Vibe solo series.