Born in Chiba Prefecture in 1988, Koizumi began teaching himself dressmaking at the age of 15. While still a university student in 2011, he launched his eponymous brand TOMO KOIZUMI, creating costumes primarily for live concerts and advertisements.
In 2019, he was discovered through social media and was invited to present his first runway show in New York.
In 2021, he designed the dress worn by the performer of the national anthem at the opening ceremony of the Tokyo 2020 Olympics.
Alongside his work as a dress designer, Koizumi has also been working on contemporary art and has held solo exhibitions in Paris and Tokyo. His works have been acquired by numerous museums, including the Metropolitan Museum of Art.
He has received several prestigious awards, including the LVMH Prize 2020 and the 39th Mainichi Fashion Grand Prix.
His clientele includes global artists such as Lady Gaga, Sam Smith, Lauryn Hill, and Björk.