She represented her country at the 2009 World Championships in Athletics and has also competed for Japan at the Asian Games and the Summer Universiade.

Born in Kagawa Prefecture, Sachiko Masumi went to Akiyoshi junior high school and competing in a variety of track and field events in her youth.

She began to have success in the long jump and in her last year of junior high school she competed at the Japanese Athletics Championships, placing third and clearing six metres for the first time.

[4] Masumi had a successive win at the national championships in 2009, clearing a personal best of 6.65 m and defeating Kumiko Ikeda.

[7] She bested her rival at the 2013 Asian Athletics Championships, however, clearing 6.55 m to win the gold medal and her first major title.