[1][2] Maehata was born in Hashimoto, Wakayama, as the daughter of a tofu producer and as a child learned to swim in the Kinokawa River.

She went on to win numerous competitions, and was sponsored to attend a women’s boarding school in Nagoya which specialized in swimming, but the sudden death of her parents in 1931 forced her to return home.

[1] During the post-Olympic celebration after her return to Japan, she stated that she was considering to retire from competitive swimming due to family issues, but then Tokyo mayor Hidejirō Nagata reportedly asked her why she did not bring back a gold medal.

[1] During the 1936 Berlin Olympics, Maehata competed in a dead heat against the reigning German national champion, Martha Genenger, winning the gold medal for the Women's 200 m breaststroke by over one second.

She was awarded the Purple Ribbon of Merit by the Japanese government in 1964 and inducted into the International Swimming Hall of Fame in 1979.