Beckett has a standard gray Imperial officer cap on as part of his disguise. He has a mustache, a goatee, and some stubble, as well as a fat chin. He has muddy armor on as part of his disguise, and a gray jacket on over it. His leg piece consists of gray pants with beige straps running across the legs. He has brown hands, presumably gloves.
At some point before 10 BBY, Tobias Beckett met the criminal and bounty hunter Aurra Sing who he pushed to her death. Sing's death was later recalled to Beckett while talking with Lando Calrissian, though Beckett claimed that he just gave Sing a push and that it was the fall that killed her.
During the Mimban campaign, Beckett was found with his crew, disguised as a Captain of the Imperial Army. At some point during the battle, Beckett asked who was in charge, since their commanding officer had recently perished. Han Solo, a mudtrooper with the 224th Imperial Armored Division, informed Beckett that he was in fact the ranking officer. Beckett then led his men through the battle. While observing a ship, he met the young Han Solo, who wanted to join them as part of their crew. A member of his crew, Rio Durant, had doubts in letting Solo join them, but Beckett decided to give the boy an opportunity by leading him to be locked for desertion. Solo was put in a chamber, where he was to be fed to the Wookiee Chewbacca. Solo ultimately was able to escape with Chewbacca, who initially intended to devour Solo. Beckett left with his crew, stealing the ship they observed earlier, but then while in mid-take-off they found Han and Chewbacca running towards them, waving for them to let them onto the ship. Beckett ordered Durant to lower the ship to let Solo and Chewie board it.
Tobias Beckett was a member of Crimson Dawn, a criminal organization led by Dryden Vos. Beckett was instructed to retrieve a crate of coaxium from a 20-T Railcrawler conveyex transport on the planet Vandor-1; he went on this mission with his lover, Val, and Durant. They were accompanied by Solo and Chewbacca.
Upon arriving at Vandor-1, the crew ate dinner over a camp fire and also had a brief conversation about Han and Chewbacca's motivation for participating in the mission. Han had simply stated that there was someone he left on Corellia 3 years ago and that he will return there for her to free her from her horrible life there. Val stated that everyone needs someone, even Beckett. Beckett begins deconstructing one of his blasters and chucks it to Han. This blaster is later kept by Han throughout the rest of his life as a smuggler and a rebel.
In the morning, Beckett, Val and Han observed the transport carrying the coaxium as well as some patrolling Viper droids, while discussing the plan for the heist. The conveyex was moving towards a bridge over a ravine. The plan was as follows: Val must place explosives on the supports of the bridge. The other members of the crew (save Durant, the pilot) were to board the conveyex and attach cables from the carriage which contained the coaxium to their ship. Then, as the conveyex neared the bridge, Val was to destroy the bridge while the crew disconnected the coaxium-carriage from the rest of the conveyex, allowing the ship to lift the target carriage away while the rest of the conveyex fell to the bottom of the ravine. Val notes that if the Viper droids were alerted, the heist would become much more difficult and prompting Han to also survey the Viper droids.
After a brief moment, the heist began. Val went further up the track to place thermal detonators, Durrant flew their ship over the transport, and Beckett, Han and Chewbacca leaped aboard the transport. They opened up a hatch and gazed upon the coaxium inside, enough to power a whole star fleet. A fight ensued with some Imperial troopers aboard the transport, but Chewbacca disconnected the troopers' portion of the conveyex, leaving them behind as the rest of the conveyex moved onwards. The crew then connected four cables to the last carriage of the conveyex to their ship in order to lift it once.
The heist would not proceed smoothly from this point, however, as Val spotted the Cloud-Riders, led by Enfys Nest, moving towards the conveyex. One cloud-rider boarded the crew's ship and had a brief firefight with Durant, who was gravely injured, beginning to pilot the ship very poorly. Val was surrounded by a swarm of viper droids. She tells Beckett over the comm how much she loved him, and decided to detonate the explosives, while still near them. Han takes over as pilot for Durrant and tried carrying the shipment with only one cable attached to the carriage. Enfys Nest and her Cloud-Riders had cut off the other three and replaced them with their own. Shortly after, Durant had perished too.
Chewbacca uncoupled the carriage with the others so that they could lift the shipment off the tracks. Han and the Cloud-Riders had to eventually lift up the shipment, for they were running out of track. Both tried to take the shipment with them but failed as they were both pulling opposite directions. As both Han and the Cloud-Riders neared a mountain, Han detached the shipment of coaxium, fearing a crash. The Cloud-Riders did so as well. The coaxium was lost. After they landed Beckett had made tombstones in remembrance of his fallen comrades.
He reported back to Dryden Vos and was able to avoid execution by promising to retrieve unrefined coaxium from Kessel. Beckett had to make room for Qi'ra on his crew in accordance with Vos' wishes.
Taken to Kessel by Lando Calrissian and L3-37 on the Millennium Falcon, Beckett successfully obtained the necessary amount of coaxium and travelled with his accomplices to Savareen so the unstable material could be refined and they could rendezvous with Dryden Vos. During the mission, Beckett posed as a guard for Qi'ra, directing the fake captives, Han and Chewie, out of the Falcon. He later follows Qi'ra, L3, the Pyke who met them and its guards. While Qi'ra went into another room to discuss with the Pyke, Beckett takes out the guards who stand outside, he after watches Qi'ra fight the Pyke. After a moment of unnerving silence from the room, he opens the door, and is only to be astonished to see a Pyke laying on the floor with Qi'ra walking out of the room telling him that she was taught Teräs Käsi by Dryden Vos. Once they got to the consoles to help Han to get to the vault of coaxium, L3 had freed some slave droids, who also freed the other slaves in the mine. The slaves inevitably rebelled against the guards allowing Beckett and the others to escape aboard the Millennium Falcon.
Once on the planet, Beckett showed his true colors to Han, Qi'ra, and Chewbacca. Once Han had told Beckett their plan he reports to Vos. Once they meet Vos, Vos surprises the team by announcing that the coaxium is fake – he reveals his "inside man," and despite Han assuming that it was Qi'ra it was indeed, Beckett. He had informed him of Han's plan to sell the real shipment to the Cloud Riders, a rebellion group led by Enfys Nest. Han announces that he anticipated Beckett's deception – the coaxium they are holding is real. He betrayed the three and abandoned Dryden. He attempted to take the coaxium for himself, but he was shot by Han. However, he praised Han for his actions right before he died.
Even though Beckett betrayed Han and Han killed him, Han, after Beckett's death, recalled to Chewbacca that Beckett said that he heard about a very big gangster putting together a job. In addition, after Beckett's death, Han started calling everyone younger than him "kid" (just like Beckett used to call Han) from the moment he reunited with Nest until his own death at the hands of his son, Kylo Ren, 44 years later in 34 ABY.
- Despite initial fan assumptions that Woody Harrelson would be portraying Han Solo's EU mentor, Garris Shrike, it was revealed he was playing a brand new character, Tobias Beckett.