Samuel was a young man of average build and height, with dark hair. His hair was parted in the center with bangs and faint sideburns. He wore the typical uniform of the 104th Training Corps.
In the year 854, his appearance remained largely unchanged. As part of the Yeagerists he was only ever seen wearing the Survey Corps' new uniform.
There is little known about Samuel's personality. He appeared to had been a fairly normal young man, concerned for the well-being of his friends and eager to join in celebrations.
As part of the Yeagerists, Samuel seemed to display a pragmatic personality. After discovering that his former comrades had betrayed Paradis, Samuel was quick to order Daz to destroy the airship they wanted to use, despite the technological advancements that would have been lost. He was also willing to shoot and possibly kill his former friends, despite his clear reluctance to accept that they were working with Marley.
On the day after the 104th Training Corps' graduation, Samuel's team is sent to clean the cannons mounted along to the top of Wall Rose in Trost District. The group discuss which branch they intend to join and Sasha Blouse reveals that she had stolen meat from the officers' rations. Initially fearing punishment for the theft, the group eventually decide to partake in it with Sasha.
The sudden appearance of the Colossus Titan causes all of the trainees to be knocked off the Wall, and Samuel is knocked unconscious by flying debris. He is saved by Sasha, who catches him by launching one of her vertical maneuvering equipment hooks into his lower calf.
In the year 854, Samuel and Daz are among the Yeagerists stationed at Paradis Island's harbor to prevent anyone from attempting to use the island's airship. The two stop Armin Arlert and Connie Springer from commandeering the airship, explaining that they are suspected of working with Marley to undermine Eren Yeager's plan to destroy the world outside of Paradis. Armin and Connie explain that they want to use the ship to pursue the Marleyan soldiers fleeing Paradis and Samuel and Daz agree to disarm the explosives placed on the ship.
Shortly afterwards, Floch Forster announces to the Yeagerists that Armin, Connie, and Mikasa Ackerman have betrayed Paradis. Daz begins rearming the explosives on the ship and Samuel shoots Armin to stop him from interfering. Samuel orders Daz to blow up the ship and holds Connie at gunpoint, lamenting that his comrades betrayed him. Samuel is momentarily distracted by the Armored and Female Titans transforming, allowing Connie to tackle him. Despite Samuel's pleas, Connie takes his gun and kills both of them.
- Samuel's fate after being rescued by Sasha in Chapter 3 was unknown and he was later stated to be deceased in the Attack on Titan Character Encyclopedia. However, this was proven to be wrong when he reappeared alive in Chapter 128.