The spirit of Zangetsu resembles a tall, 30- to 40-year-old man with unkempt facial hair and long, ragged, brown hair. He dresses in tattered, all-black garbs with narrow sunglasses and a long, flowing overcoat that flares out into ragged ends. Because of the spirit's appearance, Ichigo calls him "Old-man Zangetsu". Zangetsu has also been called the "black-clothed man".

In Bankai form, he resembles a teenage version of himself and appears to be closer to Ichigo's age