Usami was born in Numazu, Shizuoka, and raised in Kanagawa Prefecture.She was awarded Bungei Prize for her first work Kaka (かか) in 2019. She was successively awarded Mishima Yukio Prize for the same work, which made her the youngest holder of the prize.She was also awarded the 164th Akutagawa Prize for her second work Oshi, Moyu (推し、燃ゆ).