Shinichiro had unkempt short hair similar to the color of his dull black eyes. He was slim, six feet tall, and had a heart-shaped face, notably looking a lot like his younger brother Manjiro Sano. His lips were thin and he would regularly smoke a cigarette. Shinichiro is described as being "weak to women, weak in fights, but reliable." Shinichiro was a notorious delinquent with an unequaled reputation who garnered the respect of many delinquents, both inside his gang and those of rival gangs.