Nicholas Joestar was a young scrawny man who had a regular haircut save for interlaced locks of hair forming a simili-crest at the top of his head.
In the past, Nicholas is shown as kind and sympathetic to his much younger brother Johnny. He seems to be a good student too as his teachers trust him and would lend him a mouse corpse to fool his father about Danny's death.
When young Johnny once took his pet mouse Danny to secretly feed it under the table during dinner, his father, upon discovering it, ordered the child to drown the animal himself as punishment. Heartbroken, Johnny was unable to bring himself to do the deed, and followed Nicholas' suggestion to set Danny free into the woods instead.
Years later, Nicholas grew into a promising jockey-to-be, surpassing even the young Diego Brando. One day Nicholas's horse stumbled from something on the ground, which cost him his life. An onlooker claimed a white mouse was the cause of the accident – a mouse he believed to be Danny. Seven years later, it was Johnny who rose to fame as a racing prodigy. However, his father still did not acknowledge him and his feats, even asking God "why He had taken Nicholas and not Johnny".
During the fight with Axl RO, Nicholas and Danny were seen once more, manifested from Johnny's guilt over freeing Danny and accidentally leading to Nicholas' death.