Sayumi Michishige is a Japanese singer, actress and model. She is a former sixth-generation member and former leader of the J-pop group Morning Musume. Following the departure of fifth-generation member Risa Niigaki on October 12, 2013, Michishige held the longest tenure of any member in the group's history even after her graduation. She went on to hold this record until surpassed by ninth-generation members Mizuki Fukumura and Erina Ikuta in December 2022.
Michishige was born in Ube, Yamaguchi Prefecture, Japan. She joined Morning Musume in 2003 along with Eri Kamei, Miki Fujimoto, and Reina Tanaka, who all debuted with Morning Musume on the group's nineteenth single, "Shabondama". In 2005, she was assigned as mentor to seventh-generation member Koharu Kusumi, until Kusumi left the group in December 2009. Michishige was also a member of the Hello! Project unit Ecomoni, along with former Morning Musume member Rika Ishikawa.
She portrays a visual-focused, self-confident image of herself in more TV shows, often calling herself the cutest member in Morning Musume and saying that her cuteness overwhelms her poor singing skills. In one of the skits known as Hello!