Lee Seung-Jin (イ・スンジン, I Sunjin) is a midfielder for Red Bison.
He has tanned skin and is average in height. He has black hair styled into a big mohawk with one bang tied at the end and falling near his right eye, his hair is shaved at the sides which are dyed gray. He also has medium-sized black eyebrows and wears black glasses with white frames.
From his debut, he's seen with a ridicule smile on his face, but he also has a caring side as shown when he was worried about Seok Min-Woo's injury.
Lee played as a midfielder for his team Red Bison who faced Inazuma Japan as their first opponent. After Baek Shi-Woo wasted a scoring chance because of Kazemaru Ichirouta's Spinning Fence that stopped his Red Break, Red Bison started to play rough because they received an order from their coach and Baek used Bison Horn, which was able to score a goal after Park Ji-Won obstructed Endou Mamoru's view by whipping up sand. After that, Gouenji Shuuya approached Red Bison's goal, using Last Resort, which scored against Shin Rae-Won's Fire Wall. Later, Baek used Bison Horn once again, but this time it was stopped by Endou's Fuujin Raijin. In the second half, Baek, Seok and Lee Dong-Hyeok used Tokkou Buffalo Train to get in front of Inazuma Japan's goal and Baek used Red Break, which Kazemaru weakened by using his head and Endou managed to stop it using Fuujin Raijin, but Red Bison still scored after Lee picked up the loose ball and scored. Since Seok saw Baek's Orion mark, Baek gave another order to Lee and Park to knock Seok unconscious, causing him to be replaced with Son Min-Soo. In the end, Red Bison lost with a score of 3-2 after Haizaki Ryouhei and Kira Hiroto scored with Penguin The God Devil.