Yamagata Miki was born in Kamakura City, Kanagawa Prefecture in 2002. She won First Prize, Nomura Prize, Iguchi Prize, Kawai Prize, Miyake Prize and Argerich Arts Foundation Prize in the piano division of the 89th Music Competition of Japan. Yamagata was the Special Class finalist at the 44th PTNA Piano Competition. She won First Prize and Nohan Prize at the 2nd Nohan Festival Chopin in Japan Piano Competition and participated in the Nohan Festival in France. Yamagata won the most excellent prize in the young pianist division, Kanagawa Governor's Prize (Grand Prix), and First Prize in the piano division at the 35th Kanagawa Music Competition. She won First Prize in the Junior III division and the Little Pianist Prize in the 5th Ishikawa International Piano Competition. Yamagata won First Prize at the 4th Beethoven International Piano Competition Asia and won the Yokohama Sinfonietta Prize, Wakabayashi Nobu Prize, Theatre Fonte Prize, and Sagamiko Community Center Prize.
She has performed with Ueno Masahiro, Iwamura Chikara, Watanabe Kazumasa, the Polish Silesian Philharmonic Orchestra, Prima Vista String Quartet, Kanagawa Philharmonic Orchestra, Tokyo Symphony Orchestra, and Tokyo Philharmonic Orchestra. Yamagata is a first-year student in the department of instrumental music of the faculty of music at the Tokyo University of the Arts after completing its attached high school. She won the Munetsugu Tokuji scholarship of the University for 2020. Currently, Yamagata studies under Azuma Seizo and Hibiya Yukiko.