Suder first appeared in the Season 2 episode "Meld". He had been revealed by Tuvok to be a murderous sociopath and was responsible for killing a fellow crewman and attempting to cover it up as an accident. When questioned about his motive, Suder admitted he had no real reason for his actions and felt neither guilt nor remorse for what he had done. When Tuvok inquired as to why the Maquis would recruit an unstable individual like Suder, Chakotay admitted that he only recruited Suder out of necessity and did not truly know the man.
After Suder was incarcerated within his quarters, Captain Janeway was uncertain as to what to do with him since Starfleet did not execute prisoners and Voyager had only limited resources. Tuvok took it upon himself to rehabilitate Suder and help him to understand and control his violent tendencies, initiating a Vulcan mind-meld with him. This helped Suder to better understand his emotions, though it also had the temporary side effect of bringing out Tuvok's own dark impulses.
Over time, Suder showed great improvement and demonstrated a willingness to change. He accepted his punishment gladly and found himself taking an interest in botany during his confinement, being allowed to turn his quarters into an airponic laboratory where he cultivated an entirely new species of flower. He expressed a desire to contribute to Voyager's journey in a positive way and even requested that Captain Janeway allow him to adapt his new botanical skills to produce new vegetables for the ship's food supply. However, at the time of his request, Janeway was put under great stress as Voyager was currently travelling through Kazon-Nistrim territory, so she did not give Suder an immediate answer.
In the two-part episode "Basics", Voyager was taken over by the Kazon-Nistrim and the whole crew, with the exception of the Doctor and Suder, were put off the ship. Suder took to hiding in the ship's Jefferies tubes while the Doctor, as the ship's medical hologram, could not exist outside sickbay. Suder made it to sickbay and he and the Doctor formulated a strategy to retake the ship from the Kazon. Using a thoron generator to fool the internal sensors, Suder could sneak around the ship undetected and used this advantage to procure weapons. Unfortunately, it also meant that he had to kill again.
Though he despised having to take life once more, Suder knew that it was necessary if Voyager was to be reclaimed. Voyager would later come under attack by the Talaxians (led by Tom Paris who had escaped in a shuttlecraft before the ship was captured) and that provided Suder a distraction, allowing him to sneak into Main Engineering. The Doctor had relayed instructions from Paris to Suder to reroute weapons control to Engineering so that he could initiate an overload sequence that would disable Voyager's weapons and leave it defenseless. Suder infiltrated Engineering and gunned down all of the Kazon in the room before sabotaging the ship's phasers. The plan was successful, but one of the Kazon survived Suder's attack and shot him in the back before succumbing to his wounds.
After Voyager's crew were rescued from Hanon IV, Captain Janeway was informed of Suder's heroism. Tuvok offered Suder a Vulcan prayer: "May your death bring you the peace you never found in life."