Seiya Suzuki was born August 18, 1994 in Arakawa City, a special municipality within the northeastern portion of Tokyo. He attended Nishogakusha High School and while his power stood out, he emerged as the staff ace in the fall of his first year on the strength of his fastball, which touched 92 MPH. The school participated in the annual Spring and Summer Koshien competitions, but Nishogakusha High School never took home a championship while Suzuki was there.
In 2012, during the Nippon Professional Baseball Draft Conference, the right-hander was drafted by the Hiroshima Toyo Carp. The class of 2012 was particularly loaded- pitchers Shintaro Fujinami, Tomoyuki Sugano, and Shohei Ohtani were available, as were less heralded hurlers Yasuhiro Ogawa and Nao Higashihama- and Suzuki did not hear his name called until the second round.