Miles Morales is different from Peter Parker primarily due to his background and origin. While Peter Parker is a Caucasian character who gained his powers through a radioactive spider bite, Miles Morales is biracial, with an African-American father and a Puerto Rican mother. Additionally, Miles inherits his powers from a genetically engineered spider bite. These differences in ethnicity and origin bring unique perspectives and experiences to each character, making Miles Morales a distinct and culturally relevant addition to the Spider-Man universe.