Mio Sumiyama, originally from Tokyo, Japan, started dancing at the age of 3. During her training, she achieved first prizes in several competitions in Japan and became a finalist at the 2014 Youth America Grand Prix. After receiving pre-professional training from Kiyoko Kimura, she joined Tanz Akademie Zürich in 2016 under the direction of Oliver Matz and Steffi Scherzer. During her time there, Mio collaborated with choreographers such as Kinsun Chan, Seh Yun Kim, Leo Mujic, and Roberta Martins, dancing main and principal roles. In 2018, Mio performed at the Spoleto Grand Gala after winning Gold and Grand Prix at the International Ballet Competition in Spoleto. In 2019, she became a prize winner at the Prix de Lausanne, which led her to perform at the Arcotte International Ballet Performance in Tokyo as a guest dancer. Mio joined the Birmingham Royal Ballet on a Prix de Lausanne scholarship, performing in ballets like Giselle, Nutcracker, and Swan Lake, choreographed by renowned artists such as Sir Peter Wright and David Bentley. Later, Mio worked with KK International and KK Art Project, where she had a chance to explore with various choreographers like Masa Kolar, Young Soon Hue, Dimo Milev, and Yuka Oishi, performing pieces such as Square, Wave of Emotion, Wanderer, and Moirai. For the 23/24 season, Mio joined the Croatian National Ballet in Rijeka.