Sanemi is a tall, very muscular young man with a light skin tone, and long, spiky, ruffled white hair, featuring two large bangs on the left and middle side of his face. His large almond-shaped eyes have long eyelashes and purple irises with dark swirls, which turn bloodshot when he's angry. He also has dark patches beneath his eyes, making him appear perpetually tired or restless. His face and body are covered with scars, accrued over his many years of fighting demons. He cuts his hair short somewhere in between the events of the Hashira meeting and the Mugen Train incident. He is usually seen wearing a crazed expression on his face.

Sanemi wears the standard Demon Slayer Corps uniform, which is black in the manga and tinted a dark green in the anime. His uniform consists of a button-up jacket with a stand-up collar and long sleeves, featuring gold buttons and a shirt pocket on the left breast, with the kanji for Destroy engraved on the back of the collar. Beneath his uniform, he wears a white long-sleeved collared undershirt. Unlike the typical wear, Sanemi’s jacket and undershirt is left almost entirely unbuttoned, exposing his chest and toned abs, with only the lowest button fastened. The sleeves of his jacket and undershirt are rolled up to his elbows. He completes his outfit with a pair of matching tattsuke-hakama pants, fastened with a white belt. Over this, he wears a white long-sleeved haori bearing the kanji for Kill etched on the back. For legwear, Sanemi wraps his lower legs in white buckled straps instead of traditional kyahan, and wears dark green tabi socks to match his uniform tint. His footwear consists of white zōri sandals with green straps.*

Sanemi and Giyuu were by a lake training with one another. It was originally supposed to be a non-combative training session, but of course it spiraled out of control.

Mainly because of Sanemi, but Giyuu didn’t help when he refused to let up on his attacks.

After a powerful swing of his sword, Sanemi had fallen into the lake But of course Sanemi was extremely angry because of this and her ego was already damaged. Due to his aloof personality, Giyu is not close to his fellow Hashira. While some are on even terms but emotionally distant from him, others view him with apathy, or even disdain; Sanemi Shinazugawa and Obanai Iguro were particularly contemptuous of the Water Hashira due to unfoundedly misreading his aloofness as arrogance.

“… you’re movements were too sloppy.” Giyuu muttered under his breath, his voice coming across as cold and bored.