The protagonist of several stories in the Eureka Seven universe. Sumner is a young member of the prestigious and military-centric Sturgeon family. He has a deep passion for lifting thanks in no small part to Torino, one of his many older brothers, and is willing to lift against school regulation although it is punishable by immediate expulsion.
In the story we see Sumner grow from a 14 year old in boarding school to an 18 year old man joining the New Wave. Along the way he has many ups and down and struggles to decide what he wants to do with his life. As a Sturgeon boy he is expected to begin attending Officer Candidate School after his boarding school graduation. He develops relationships with several characters that will be present later in New Wave along the way.
Sumner Sturgeon (サムナ・スタージョン Samuna Sutājon) is from the Sturgeon family, a prestigious family known for producing top-quality soldiers. His father, Bernard Sturgeon, is outspoken against the use of LFOs in the military, and is the first reason why he was recruited into New Wave Academy: to counter his father's actions. He possesses great skill in lifting and LFO piloting. Upon graduation, Sumner is transferred to Sawyer Team — an elite KLF group in the military that is said to be almost on par with Holland's SOF. Sumner never had any ambitions, goals or dreams before joining New Wave Academy. His only reason for joining was so that he could pilot the best LFOs. It is there he meets Ruri for the first time as a fellow cadet in New Wave. It is later revealed that Ruri leaves New Wave Academy upon discovering a dark truth about the academy and seeks refuge within the Vodarac, to whom she appears to be directly affiliated with at present. Sumner is unaware about Ruri's reasons for leaving, and continues to excel in the academy and serve as Sawyer Team's ace pilot. The two meet in the future during a solo mission given to Sumner to investigate the weapons black market in his area, but she later escapes as she was somewhat involved with the black market.
Sumner is on patrol on another mission not long after Holland's mutiny, when he first meets a younger Moondoggie. He asks Moondoggie's purpose in town to which Moondoggie replied that he was there to meet Holland and join up with Gekkostate. Following a series of situations designed to draw away the Sawyer team from the tower, Sumner realizes the immediate Vodarac threat at the tower. It is then when meets Sumner meets Ruri once more while she is on a mission for the Vodarac (or possibly Gekkostate). Her objective was to secure the Nirvash and deliver it to Holland, while Sumner's objective was to protect the tower against terrorist attacks by the Vodarac.
The two confront one another and it is then when Sumner's captain intervenes and shoots Ruri, injuring her arm. Sumner finally begins to realize the lies of the military, his feelings for Ruri, and what he believes is right. Surprising the captain and the Sawyer team (all of whom were his close friends), Sumner defects from the military to save Ruri from certain death. He manages to save her and has her board his LFO and escape with the promise that they will meet at their special place while he takes it upon himself to complete Ruri's objective. Sumner faces off against his teammates and defeats them while riding the Nirvash. His captain makes one last stand against Sumner and two battle at it, on military airport grounds and while airborne on refboards. Sumner proves to be the more skilled pilot and kills his captain in their aerial battle. Sumner then completes Ruri's mission and hands over the Nirvash to Holland. When asked about the purpose of the Nirvash, Holland merely replied that the Nirvash was meant to be piloted by only one person who can use it properly. Sumner sees over Holland's shoulder a younger Eureka staring at the Nirvash. Holland then recognizes Sumner's piloting and ref boarding abilities and invites him to join Gekkostate. Sumner declines saying that he wants to search for Ruri. Gekkostate departs with the Nirvash, leaving Sumner behind. While sitting at campfire in the desert, a vehicle comes along that Sumner hails down. The driver is Moondoggie and he offers Sumner a ride out of the desert. TR1: New Wave ends here, with the story to be continued on New Vision.
A few years later Sumner and Ruri are reunited. The two became involved with the refboard manufacturers known as Azure. Along with Moondoggie, they briefly traveled with Azure, sabotaging several military installations along the way. Eventually, they learned that Azure's activities were tied to a conspiracy within the military, spearheaded by former New Wave student Steven Bisson and Azure's leader, Roddy Flame. They were responsible for the proliferation of Compac Feedback Systems (CFS) throughout the military's LFO pilots, and were planning on using the technology to revolt and cause mass destruction. Sumner, Ruri, and Moondoggie fought against Azure and their Army benefactors, eventually defeating Steven and Flame and ending the threat. While Moondoggie returned to Gekkostate, Sumner and Ruri stayed together.