Ume Matsuzaka teaches the Rose Class at Futaba Kindergarten as a 24-year-old unmarried woman. Her name "Ume" causes significant discomfort due to associations with meanings like "low class" or "third rate," leading her to insist others avoid using it. Financially constrained, she maintains a stylish public image while secretly struggling to afford accessories and fashionable items. She resides in a notably inexpensive, poorly maintained apartment and subsists on minimal-cost foods like noodles and lettuce when funds run low before payday. Despite regularly expressing frustration with her job—particularly regarding Shinnosuke Nohara and his friends—and threatening to transfer to a more prestigious school, her commitment to Futaba Kindergarten remains unwavering. She once rejected a man who mocked the kindergarten while offering her a better position elsewhere.

Her dynamic with Sunflower Class teacher Midori Ishizaka features rivalry and frequent bickering, though beneath this lies genuine care; Ume assists Midori in reconciling with her future husband, Junichi Ishizaka. Romantically, her experiences involve comedic misfortunes, with dates often disrupted by Shinnosuke and his friends. This pattern persisted through relationships with Kawaguchi, Tokuro, and later Shingo Kakeda. A tragic development in the manga sees her fiancé Tokuro die in a terrorist attack overseas, plunging Ume into severe depression where she contemplates suicide.

Ume possesses acrobatic abilities from past dance classes, showcased when she avoids tearing a new dress by executing a flip during a fall. She has two sisters named Matsu and Take. In non-canonical appearances like the Nintendo DS game *Crayon Shin-chan: Arashi Wo Yobu Nutte Crayoon Daisakusen*, she assumes a villainous witch role in a Hansel & Gretel-inspired stage. Within the film *Pursuit of the Balls of Darkness*, her involvement is minimal, limited to a brief cameo questioning Shinnosuke's absence upon the Nohara family's return.