Tetsunosuke Goujin hails from Inakunijima Island, where he played for the local Inakuni soccer team prior to its disbandment. After the team relocated to Tokyo, he joined Inakuni Raimon as a forward, competing in the Football Frontier tournament. He possesses a tall, muscular build with dark skin, messy purple hair, small black irises, a square jaw, and thin eyebrows. Off the field, he typically wears a black jacket featuring white stripes on the sleeves and white chest pockets, paired with gray pants and light shoes.

Goujin is hot-blooded and hard-working, yet displays gaps in emotional resilience and general knowledge, famously unaware of legendary soccer players like Endou Mamoru. He frequently misremembers terminology, notably confusing the hissatsu technique "Fire Tornado" with "Fire Lemonade" during training. This misnomer ultimately christened his signature shooting technique, which evolved extensively over multiple episodes into "Fire Lemonade Rising." He is easily agitated by criticism or perceived slights and exhibits overconfidence in his abilities, often expressing frustration when benched. Despite this, he possesses a determined spirit and occasionally cooperates with teammates, such as fist-bumping Kozoumaru Sasuke after a goal.

Goujin contributed to key Inakuni Raimon victories. Against Minodouzan, he attempted "Fire Lemonade" unsuccessfully but celebrated Kozoumaru's successful "Fire Tornado." In the match versus Mikage Sennou, he scored the third goal following coach Zhao Jinyun's strategic instructions, securing a 4–0 win. His competitive drive surfaced when he envied teammates like Hiyori for mastering their hissatsu techniques first.

In "Orion no Kokuin," Goujin was selected as a forward for Inazuma Japan, representing Japan in the FFI tournament. Initially surprised by his inclusion over other Inakuni players like Michinari Tatsumi, he joined the team at the Kawaguchiko Sports Center. Under coach Zhao Jinyun, he participated in early training sessions, including a challenging match against Clario Orvan of Barcelona Orb that ended in defeat but motivated the team. Goujin primarily served as a bench player during Inazuma Japan's preliminary matches in the Asian representative rounds, functioning as a strategic reserve or "secret weapon" similar to Fudou Akio's role in the original Inazuma Japan squad.

Goujin's hissatsu techniques include the shooting moves "Fire Lemonade" and "Fire Lemonade Rising," alongside "Dragon Crash" in spin-off games like "Inazuma Eleven AC: Dream Battle" and "Inazuma Eleven SD." His gameplay stats in "Inazuma Eleven SD" emphasize kicking power (61) and dribbling (43) over defensive capabilities.