Tomar-Re was a Xudarian, a race of aliens from the planet Xudar in Sector 2813 (in his first Pre-Crisis appearance he claimed it was Sector 9). He was a scientist on his homeworld before joining the Green Lantern Corps and becoming the Green Lantern of Sector 2813. Tomar-Re became a pivotal member of the Corps, training new members, like Arisia, and serving in the Honor Guard. He investigated reports of abuses of power by Sinestro on Korugar. He was close friends with Abin Sur, Green Lantern of neighboring sector 2814. He was also the first Lantern to meet Sur's replacement, Hal Jordan, and the two got along equally well. Pre-Crisis they first met when Tomar contacted Green Lantern about a threat to a world in his sector, which was happening at the same time alien invaders were attacking Tomar's world. Hal stopped the threat, then helped Tomar defeat the invaders, who hastily left the world. Hal first found out about the Guardians from Tomar, who mentioned they wanted the Green Lanterns to be equal which is why the Power Battery recharges their rings for the same time period. In the Post-Crisis timeline, that friendship is deepened further in that the rookie Jordan met him soon after being recruited. Jordan was brought to him by his power ring to help with his difficulties with handling the weapon and Tomar-Re not only guided the Terran to GLC headquarters for the optional training program, but also provided valuable emotional support during this difficult time.
Tomar's most famous mission while serving in the Corps dealt with the planet Krypton. Krypton, a planet in sector 2813, was growing increasingly unstable. It was due to explode, caused by internal pressures deep inside the planet's core. Tomar-Re sought to use a rare compound called stellarium to absorb some of the tectonic pressure, thus saving the Kryptonians. He gathered the compound, and was en route to Krypton when a yellow solar flare blinded him, and forced him to drop the stellarium. He quickly recovered, but discovered he was blind. He gathered what little stellarium he could without his sight, and proceeded towards Krypton. He was closing in when his vision started to clear. The first thing he saw upon his sight returning was Krypton exploding. The Guardians recovered Tomar and brought him back to Oa, where he healed and rested.
Tomar was retired when the Anti-Monitor sought to conquer the multiverse. He still served alongside the Corps, including John Stewart, who had become the GL for 2814. The war against the Anti-Monitor would be Tomar's final fight, as he was killed by the villain known as Goldface. Before his death, Tomar-Re selected Stewart to be his replacement, thus forcing John's ring to go to Jordan, who had resigned from the Corps, and returning him to the organization (Green Lantern vol. 2, #198).
After the events of the War of the Green Lanterns, Hal Jordan and Sinestro are trapped in the Dead Zone by the Guardians of the Universe (who have become unemotional), until they encounter a mysterious figure lurking in the zone observing them. This mysterious stranger says he was Hal's friend and Sinestro's enemy, and states that they are both dead. The mysterious stranger is revealed to be Tomar-Re (who was undead), asking Hal and Sinestro to stop Volthoom (The First Lantern), before he goes about bringing changes to reality in history. Hal and Sinestro are then confronted by the dead members in the Dead Zone. When Hal questions how did Tomar-Re knew this, he explains that those beings who had died gathered information in the Dead Zone. Later, they are approached by Green Lantern Simon Baz who was transported by Black Hand to the Dead Zone and pulled him back after he split his ring which Sinestro claimed and unintentionally went with him leaving Hal trapped. Tomar-Re view that Sinestro will not takes Volthoom down easily.
Tomar-Re has a silent cameo in the Justice League two-part episode "In Blackest Night".
Tomar-Re appears in the Justice League Unlimited episode "The Return".
Tomar-Re made an appearance in the Duck Dodgers episode "The Green Loontern". He was the first Green Lantern to be seen captured. He was voiced by Joe Alaskey, who was uncredited for the role.
Although Tomar-Re does not appear in the Legion of Super Heroes animated series, natives of his homeworld Xudar as well as Barrio III do appear.
Tomar-Re was briefly seen in the episode "Ring Toss" of The Batman. Hal Jordan played a recording for Batman in which Tomar-Re relayed the information about Sinestro's escape from prison. Voice actor has not been confirmed.
Tomar-Re is seen as part of the Lantern Corps in Batman: The Brave and the Bold episode "The Eyes of Despero". His home planet of Xudar also appears (listed in the captions as "Exudar"), and is taken over by Despero.
Tomar-Re appears in the first season of Green Lantern: The Animated Series, voiced by Jeff Bennett.
John Larroquette voices Tomar-Re in Green Lantern: First Flight. During the course of events he is betrayed by Sinestro, who kills him using his newly obtained yellow ring.
Geoffrey Rush voiced Tomar-Re in the film, Green Lantern directed by Martin Campbell. As in the comics, he is the first fellow Green Lantern Hal Jordan meets upon recruitment and it proves a pleasant encounter as the soft-spoken veteran provides Hal with an orientation tour of Oa and the Corps. He appears unmasked as his identity needs no protection in Oa, and his appearance is very similar to the comics, in which he seems to exhibit both avian and fish traits in morphology, although he tells Hal in the film that the DNA of his race is similar to that of the ichthyologic species in Hal's planet. Furthermore, when Jordan is rendered unconscious upon defeating Parallax, Tomar-Re joins with Sinestro and Kilowog in rescuing Hal, keeping him from falling into the Sun.
Tomar-Re appears in Green Lantern: Emerald Knights voiced by James Arnold Taylor.