Born in Fukushima, Umetsu started playing baseball in Grade 2 with local club team Minami Koizumi Mets.

[5] In 2015, Umetsu was part of the active squad in his freshman year and made his starting debut against Tokyo Agricultural University in the 2nd game of the fall season.

[9] In the lead-up to the 2018 NPB Draft, Umetsu was one of three pitchers from Toyo University expected to go in the top rounds alongside Taiga Kamichatani and Hiroshi Kaino.

[13] On 3 September, Umetsu won his third consecutive game since debut against the Yomiuri Giants marking the best winning record for a rookie, Dragons pitcher since Shinichi Kondō went 3-0 to start his career in 1987.

[16] At high school, Umetsu was known for his large appetite having held the record for most bowls or ramen eaten at Shodai Yokarōmon's (初代よかろうもん) Sendai Station store.