Jasper was part of the original 100. He was arrested along with his best friend, Monty Green, for stealing herbs from the Ark garden and sent to juvenile lockup. Jasper was a Gunner for the Delinquents against the Woods Clan. Jasper also served as the primary chemist for the 100's time on Earth.
Jasper battled PTSD that developed after he was speared in the chest in Pilot. This has continued on throughout the segundo season. He was initially supposed to be a minor character that died in the Pilot but his fate was changed due to the cast and crew liking his character so much.
While inside Mount Weather, Jasper became dependent on the Mountain Men, believing they had the Delinquents' best interests at heart. When Jasper learned the truth, however, he was determined to save his people and leave Mount Weather, becoming a leader for the Delinquents trapped inside.
In Season Three, Jasper became severely depressed due to Maya's death, and he developed grudges against Monty and Clarke. He made several attempts to drink himself to death, but fought against it. He later joined a resistance of Sky People, who fought the Artificial Intelligence A.L.I.E. after she took control of nearly all the Arkadians and residents of Polis. He eventually took the chip himself to try and relieve the pain of losing Maya. He was released after Clarke pulls A.L.I.E.'s kill switch.
In Season Four, Jasper was much of the same, even trying to kill himself with a revolver. However, after learning that there was another nuclear apocalypse looming and there was very little hope for any of them to survive, he became más cheerful. He entered in a mode of disregarding his actions, believing that since they were all going to die soon anyway that he won't be around to reap the consequences. When the rest of the Sky People leave to go to the segundo Dawn Bunker, Jasper decided to stay behind at Arkadia in order to die. He had one last talk with Monty before he died from overdosing on the hallucinogenic Jobi Nuts, committing suicide.
